1
|
Bulbucan C, Preger C, Kostanyan A, Jensen KMØ, Kokkonen E, Piamonteze C, Messing ME, Westerström R. Large exchange bias in Cr substituted Fe 3O 4 nanoparticles with FeO subdomains. Nanoscale 2021; 13:15844-15852. [PMID: 34518859 PMCID: PMC8485415 DOI: 10.1039/d1nr04614d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
Tuning the anisotropy through exchange bias in bimagnetic nanoparticles is an active research strategy for enhancing and tailoring the magnetic properties for a wide range of applications. Here we present a structural and magnetic characterization of unique FeCr-oxide nanoparticles generated from seed material with a Fe : Cr ratio of 4.71 : 1 using a physical aerosol method based on spark ablation. The nanoparticles have a novel bimagnetic structure composed of a 40 nm ferrimagnetic Cr-substituted Fe3O4 structure with 4 nm antiferromagnetic FexO subdomains. Cooling in an applied magnetic field across the Néel temperature of the FexO subdomains results in a significant shift in the hysteresis, demonstrating the presence of a large exchange bias. The observed shift of μ0HE = 460 mT is among the largest values reported for FexO-Fe3O4-based nanoparticles and is attributed to the large antiferromagnetic-ferrimagnetic interface area provided by the subdomains.
Collapse
Affiliation(s)
- Claudiu Bulbucan
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Synchrotron radiation research, Lund University, SE-22100 Lund, Sweden.
| | - Calle Preger
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Aram Kostanyan
- Physik-Institut, Universität Zürich, CH-8057 Zürich, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | | | - Esko Kokkonen
- MAX IV Laboratory, Lund University, PO Box 118, 221 00, Lund, Sweden
| | - Cinthia Piamonteze
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Maria E Messing
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Synchrotron radiation research, Lund University, SE-22100 Lund, Sweden.
- Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - Rasmus Westerström
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Synchrotron radiation research, Lund University, SE-22100 Lund, Sweden.
| |
Collapse
|
2
|
Krylov D, Velkos G, Chen CH, Büchner B, Kostanyan A, Greber T, Avdoshenko SM, Popov AA. Magnetic hysteresis and strong ferromagnetic coupling of sulfur-bridged Dy ions in clusterfullerene Dy 2S@C 82. Inorg Chem Front 2020; 7:3521-3532. [PMID: 33442482 PMCID: PMC7116581 DOI: 10.1039/d0qi00771d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two isomers of metallofullerene Dy2S@C82 with sulfur-bridged Dy ions exhibit broad magnetic hysteresis with sharp steps at sub-Kelvin temperature. Analysis of the level crossing events for different orientations of a magnetic field showed that even in powder samples, the hysteresis steps caused by quantum tunneling of magnetization can provide precise information on the strength of intramolecular Dy⋯Dy inter-actions. A comparison of different methods to determine the energy difference between ferromagnetic and antiferromagnetic states showed that sub-Kelvin hysteresis gives the most robust and reliable values. The ground state in Dy2S@C82 has ferromagnetic coupling of Dy magnetic moments, whereas the state with antiferromagnetic coupling in C s and C 3v cage isomers is 10.7 and 5.1 cm-1 higher, respectively. The value for the C s isomer is among the highest found in metallofullerenes and is considerably larger than that reported in non-fullerene dinuclear molecular magnets. Magnetization relaxation times measured in zero magnetic field at sub-Kelvin temperatures tend to level off near 900 and 3200 s in C s and C 3v isomers. These times correspond to the quantum tunneling relaxation mechanism, in which the whole magnetic moment of the Dy2S@C82 molecule flips at once as a single entity.
Collapse
Affiliation(s)
- Denis Krylov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany.,Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Chia-Hsiang Chen
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Aram Kostanyan
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Thomas Greber
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Stanislav M Avdoshenko
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstraße 20, 01069 Dresden, Germany
| |
Collapse
|
3
|
Spree L, Schlesier C, Kostanyan A, Westerström R, Greber T, Büchner B, Avdoshenko SM, Popov AA. Single-Molecule Magnets DyM 2 N@C 80 and Dy 2 MN@C 80 (M=Sc, Lu): The Impact of Diamagnetic Metals on Dy 3+ Magnetic Anisotropy, Dy⋅⋅⋅Dy Coupling, and Mixing of Molecular and Lattice Vibrations. Chemistry 2020; 26:2436-2449. [PMID: 31774196 PMCID: PMC7065109 DOI: 10.1002/chem.201904879] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Indexed: 01/11/2023]
Abstract
The substitution of scandium in fullerene single-molecule magnets (SMMs) DySc2 N@C80 and Dy2 ScN@C80 by lutetium has been studied to explore the influence of the diamagnetic metal on the SMM performance of dysprosium nitride clusterfullerenes. The use of lutetium led to an improved SMM performance of DyLu2 N@C80 , which shows a higher blocking temperature of magnetization (TB =9.5 K), longer relaxation times, and broader hysteresis than DySc2 N@C80 (TB =6.9 K). At the same time, Dy2 LuN@C80 was found to have a similar blocking temperature of magnetization to Dy2 ScN@C80 (TB =8 K), but substantially different interactions between the magnetic moments of the dysprosium ions in the Dy2 MN clusters. Surprisingly, although the intramolecular dipolar interactions in Dy2 LuN@C80 and Dy2 ScN@C80 are of similar strength, the exchange interactions in Dy2 LuN@C80 are close to zero. Analysis of the low-frequency molecular and lattice vibrations showed strong mixing of the lattice modes and endohedral cluster librations in k-space. This mixing simplifies the spin-lattice relaxation by conserving the momentum during the spin flip and helping to distribute the moment and energy further into the lattice.
Collapse
Affiliation(s)
- Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | - Christin Schlesier
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | - Aram Kostanyan
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
| | - Rasmus Westerström
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
- The Division of Synchrotron Radiation ResearchLund University22100LundSweden
| | - Thomas Greber
- Physik-Institut der Universität ZürichWinterthurerstr. 1908057ZürichSwitzerland
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| | | | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden)01069DresdenGermany
| |
Collapse
|
4
|
Liu F, Velkos G, Krylov DS, Spree L, Zalibera M, Ray R, Samoylova NA, Chen CH, Rosenkranz M, Schiemenz S, Ziegs F, Nenkov K, Kostanyan A, Greber T, Wolter AUB, Richter M, Büchner B, Avdoshenko SM, Popov AA. Air-stable redox-active nanomagnets with lanthanide spins radical-bridged by a metal-metal bond. Nat Commun 2019; 10:571. [PMID: 30718550 PMCID: PMC6362165 DOI: 10.1038/s41467-019-08513-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/11/2019] [Indexed: 12/02/2022] Open
Abstract
Engineering intramolecular exchange interactions between magnetic metal atoms is a ubiquitous strategy for designing molecular magnets. For lanthanides, the localized nature of 4f electrons usually results in weak exchange coupling. Mediating magnetic interactions between lanthanide ions via radical bridges is a fruitful strategy towards stronger coupling. In this work we explore the limiting case when the role of a radical bridge is played by a single unpaired electron. We synthesize an array of air-stable Ln2@C80(CH2Ph) dimetallofullerenes (Ln2 = Y2, Gd2, Tb2, Dy2, Ho2, Er2, TbY, TbGd) featuring a covalent lanthanide-lanthanide bond. The lanthanide spins are glued together by very strong exchange interactions between 4f moments and a single electron residing on the metal–metal bonding orbital. Tb2@C80(CH2Ph) shows a gigantic coercivity of 8.2 Tesla at 5 K and a high 100-s blocking temperature of magnetization of 25.2 K. The Ln-Ln bonding orbital in Ln2@C80(CH2Ph) is redox active, enabling electrochemical tuning of the magnetism. Dilanthanide complexes that possess radical bridges exhibit enhanced magnetic exchange coupling, affording molecular magnets with high blocking temperatures. Here, the authors explore a series of dilanthanide-encapsulated fullerenes where the radical bridge is taken to its limit and the role is played by a single unpaired electron.
Collapse
Affiliation(s)
- Fupin Liu
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany.
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Denis S Krylov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Michal Zalibera
- Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology, Radlinského 9, 81237, Bratislava, Slovakia
| | - Rajyavardhan Ray
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany.,Dresden Center for Computational Materials Science (DCMS), TU Dresden, D-01062, Dresden, Germany
| | - Nataliya A Samoylova
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Chia-Hsiang Chen
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Marco Rosenkranz
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Sandra Schiemenz
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Frank Ziegs
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Konstantin Nenkov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Aram Kostanyan
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Thomas Greber
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Anja U B Wolter
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Manuel Richter
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany.,Dresden Center for Computational Materials Science (DCMS), TU Dresden, D-01062, Dresden, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Stanislav M Avdoshenko
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany.
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069, Dresden, Germany.
| |
Collapse
|
5
|
Avdoshenko SM, Fritz F, Schlesier C, Kostanyan A, Dreiser J, Luysberg M, Popov AA, Meyer C, Westerström R. Partial magnetic ordering in one-dimensional arrays of endofullerene single-molecule magnet peapods. Nanoscale 2018; 10:18153-18160. [PMID: 30132489 PMCID: PMC6839967 DOI: 10.1039/c8nr05386c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The magnetic ordering and bistability of one-dimensional chains of endofullerene Dy2ScN@C80 single-molecule magnets (SMMs) packed inside single-walled carbon nanotubes (SWCNTs) have been studied using high-resolution transmission electron microscopy (HRTEM), X-ray magnetic circular dichroism (XMCD), and ab initio calculations. X-ray absorption measurements reveal that the orientation of the encapsulated endofullerenes differs from the isotropic distribution in the bulk sample, indicating a partial ordering of the endofullerenes inside the SWCNTs. The effect of the one-dimensional packing was further investigated by ab initio calculations, demonstrating that for specific tube diameters, the encapsulation is leading to energetically preferential orientations of the endohedral clusters. Additionally, element-specific magnetization curves reveal a decreased magnetic bistability of the encapsulated Dy2ScN@C80 SMMs compared to the bulk analog.
Collapse
Affiliation(s)
| | - Fabian Fritz
- Department of Physics, University Osnabrück, 49076 Osnabrück, Germany
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Christin Schlesier
- Leibniz Institute for Solid State and Materials Research (IFW), 01069 Dresden, Germany
| | - Aram Kostanyan
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Martina Luysberg
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials Research (IFW), 01069 Dresden, Germany
| | - Carola Meyer
- Department of Physics, University Osnabrück, 49076 Osnabrück, Germany
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | | |
Collapse
|
6
|
Schlesier C, Spree L, Kostanyan A, Westerström R, Brandenburg A, Wolter AUB, Yang S, Greber T, Popov AA. Strong carbon cage influence on the single molecule magnetism in Dy-Sc nitride clusterfullerenes. Chem Commun (Camb) 2018; 54:9730-9733. [PMID: 30079423 PMCID: PMC6837867 DOI: 10.1039/c8cc05029e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic properties of endohedral metallofullerenes with nitride clusters DySc2N and Dy2ScN and different carbon cages are studied by SQUID magnetometry. All molecules behave as single molecule magnets (SMMs) and exhibit magnetic hysteresis. It is found that the blocking temperature of magnetization and relaxation times strongly depend on the fullerene cage, with the C80-Ih isomer offering the best SMM properties.
Collapse
Affiliation(s)
- Christin Schlesier
- Leibniz Institute for Solid State and Materials Research (IFW), D-01069 Dresden, Germany.
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW), D-01069 Dresden, Germany.
| | - Aram Kostanyan
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Rasmus Westerström
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Ariane Brandenburg
- Leibniz Institute for Solid State and Materials Research (IFW), D-01069 Dresden, Germany.
| | - Anja U B Wolter
- Leibniz Institute for Solid State and Materials Research (IFW), D-01069 Dresden, Germany.
| | - Shangfeng Yang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Thomas Greber
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW), D-01069 Dresden, Germany.
| |
Collapse
|
7
|
Kostanyan A, Westerström R, Zhang Y, Kunhardt D, Stania R, Büchner B, Popov AA, Greber T. Switching Molecular Conformation with the Torque on a Single Magnetic Moment. Phys Rev Lett 2017; 119:237202. [PMID: 29286680 DOI: 10.1103/physrevlett.119.237202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Indexed: 06/07/2023]
Abstract
For the endohedral fullerene molecule HoLu_{2}N@C_{80}, it is shown that the endohedral HoLu_{2}N unit may be oriented in a magnetic field. The Ho magnetic moment is fixed in the strong ligand field and aligns along the holmium-nitrogen axis. The torque of a magnetic field on the Ho magnetic moment leads to a hopping bias of the endohedral unit inclining to an orientation parallel to the externally applied field. This endohedral cluster distribution remains frozen below the onset of thermally induced rotation of the endohedral units. We derive an analytical statistical model for the description of the effect that scales below 7 T with the square of the external field strength, and that allows us to resolve the freezing temperature of the endohedral hopping motion. The freezing temperature is around 55 K and depends on the cooling rate, which in turn determines an activation energy for the hopping motion of 185 meV and a prefactor of 1.8×10^{14} s^{-1}. For TbSc_{2}N@C_{80} we find the same behavior with a 3.5% higher freezing temperature.
Collapse
Affiliation(s)
- Aram Kostanyan
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Rasmus Westerström
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
- Division of Synchrotron Radiation Research, Institute of Physics, University of Lund, SE-221 00 Lund, Sweden
| | - Yang Zhang
- Leibniz Institute of Solid State and Materials Research, Dresden, D-01069 Dresden, Germany
| | - David Kunhardt
- Leibniz Institute of Solid State and Materials Research, Dresden, D-01069 Dresden, Germany
| | - Roland Stania
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Bernd Büchner
- Leibniz Institute of Solid State and Materials Research, Dresden, D-01069 Dresden, Germany
| | - Alexey A Popov
- Leibniz Institute of Solid State and Materials Research, Dresden, D-01069 Dresden, Germany
| | - Thomas Greber
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| |
Collapse
|
8
|
Fritz F, Westerström R, Kostanyan A, Schlesier C, Dreiser J, Watts B, Houben L, Luysberg M, Avdoshenko SM, Popov AA, Schneider CM, Meyer C. Nanoscale x-ray investigation of magnetic metallofullerene peapods. Nanotechnology 2017; 28:435703. [PMID: 28885185 DOI: 10.1088/1361-6528/aa8b4c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Endohedral lanthanide ions packed inside carbon nanotubes (CNTs) in a one-dimensional assembly have been studied with a combination of high resolution transmission electron microscopy (HRTEM), scanning transmission x-ray microscopy (STXM), and x-ray magnetic circular dichroism (XMCD). By correlating HRTEM and STXM images we show that structures down to 30 nm are resolved with chemical contrast and record x-ray absorption spectra from endohedral lanthanide ions embedded in individual nanoscale CNT bundles. XMCD measurements of an Er3N@C80 bulk sample and a macroscopic assembly of filled CNTs indicate that the magnetic properties of the endohedral Er3+ ions are unchanged when encapsulated in CNTs. This study demonstrates the feasibility of local magnetic x-ray characterisation of low concentrations of lanthanide ions embedded in molecular nanostructures.
Collapse
Affiliation(s)
- Fabian Fritz
- Department of Physics, University Osnabrück, D-49076 Osnabrück, Germany. Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany. JARA-Fundamentals of Future Information Technologies, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Chen CH, Krylov DS, Avdoshenko S, Liu F, Spree L, Yadav R, Alvertis A, Hozoi L, Nenkov K, Kostanyan A, Greber T, Wolter AUB, Popov AA. Selective arc-discharge synthesis of Dy 2S-clusterfullerenes and their isomer-dependent single molecule magnetism. Chem Sci 2017; 8:6451-6465. [PMID: 29263779 PMCID: PMC5734629 DOI: 10.1039/c7sc02395b] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/29/2017] [Indexed: 01/04/2023] Open
Abstract
A method for the selective synthesis of sulfide clusterfullerenes Dy2S@C2n is developed. Addition of methane to the reactive atmosphere reduces the formation of empty fullerenes in the arc-discharge synthesis, whereas the use of Dy2S3 as a source of metal and sulfur affords sulfide clusterfullerenes as the main fullerene products along with smaller amounts of carbide clusterfullerenes. Two isomers of Dy2S@C82 with Cs(6) and C3v(8) cage symmetry, Dy2S@C72-Cs(10528), and a carbide clusterfullerene Dy2C2@C82-Cs(6) were isolated. The molecular structure of both Dy2S@C82 isomers was elucidated by single-crystal X-ray diffraction. SQUID magnetometry demonstrates that all of these clusterfullerenes exhibit hysteresis of magnetization, with Dy2S@C82-C3v(8) being the strongest single molecule magnet in the series. DC- and AC-susceptibility measurements were used to determine magnetization relaxation times in the temperature range from 1.6 K to 70 K. Unprecedented magnetization relaxation dynamics with three consequent Orbach processes and energy barriers of 10.5, 48, and 1232 K are determined for Dy2S@C82-C3v(8). Dy2S@C82-Cs(6) exhibits faster relaxation of magnetization with two barriers of 15.2 and 523 K. Ab initio calculations were used to interpret experimental data and compare the Dy-sulfide clusterfullerenes to other Dy-clusterfullerenes. The smallest and largest barriers are ascribed to the exchange/dipolar barrier and relaxation via crystal-field states, respectively, whereas an intermediate energy barrier of 48 K in Dy2S@C82-C3v(8) is assigned to the local phonon mode, corresponding to the librational motion of the Dy2S cluster inside the carbon cage.
Collapse
Affiliation(s)
- Chia-Hsiang Chen
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Denis S. Krylov
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Stanislav M. Avdoshenko
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Ravi Yadav
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Antonis Alvertis
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Liviu Hozoi
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Konstantin Nenkov
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Aram Kostanyan
- Physik-Institut , Universität Zürich , Zürich , Switzerland
| | - Thomas Greber
- Physik-Institut , Universität Zürich , Zürich , Switzerland
| | - Anja U. B. Wolter
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials Research Dresden , 01069 Dresden , Germany .
| |
Collapse
|
10
|
Liu F, Krylov DS, Spree L, Avdoshenko SM, Samoylova NA, Rosenkranz M, Kostanyan A, Greber T, Wolter AUB, Büchner B, Popov AA. Single molecule magnet with an unpaired electron trapped between two lanthanide ions inside a fullerene. Nat Commun 2017; 8:16098. [PMID: 28706223 PMCID: PMC5519982 DOI: 10.1038/ncomms16098] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/30/2017] [Indexed: 01/04/2023] Open
Abstract
Increasing the temperature at which molecules behave as single-molecule magnets is a serious challenge in molecular magnetism. One of the ways to address this problem is to create the molecules with strongly coupled lanthanide ions. In this work, endohedral metallofullerenes Y2@C80 and Dy2@C80 are obtained in the form of air-stable benzyl monoadducts. Both feature an unpaired electron trapped between metal ions, thus forming a single-electron metal-metal bond. Giant exchange interactions between lanthanide ions and the unpaired electron result in single-molecule magnetism of Dy2@C80(CH2Ph) with a record-high 100 s blocking temperature of 18 K. All magnetic moments in Dy2@C80(CH2Ph) are parallel and couple ferromagnetically to form a single spin unit of 21 μB with a dysprosium-electron exchange constant of 32 cm−1. The barrier of the magnetization reversal of 613 K is assigned to the state in which the spin of one Dy centre is flipped. Single molecule magnets have demonstrated promise for information storage, molecular spintronics and quantum computing, but are limited by their low operational temperatures. Here, Popov and coworkers prepare a SMM with a high blocking temperature of 18 K by trapping two lanthanide ions with a single-electron bond inside a fullerene.
Collapse
Affiliation(s)
- Fupin Liu
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Denis S Krylov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Stanislav M Avdoshenko
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Nataliya A Samoylova
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Marco Rosenkranz
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Aram Kostanyan
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Thomas Greber
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Anja U B Wolter
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| |
Collapse
|
11
|
Liu F, Wang S, Gao CL, Deng Q, Zhu X, Kostanyan A, Westerström R, Jin F, Xie SY, Popov AA, Greber T, Yang S. Mononuclear Clusterfullerene Single-Molecule Magnet Containing Strained Fused-Pentagons Stabilized by a Nearly Linear Metal Cyanide Cluster. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611345] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Fupin Liu
- Hefei National Laboratory for Physical Sciences at Microscale; CAS Key Laboratory of Materials for Energy Conversion; Department of Materials Science and Engineering; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 China
| | - Song Wang
- Hefei National Laboratory for Physical Sciences at Microscale; CAS Key Laboratory of Materials for Energy Conversion; Department of Materials Science and Engineering; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 China
| | - Cong-Li Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials); College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Qingming Deng
- Leibniz Institute for Solid State and Materials Research Dresden; Helmholtzstrasse 20 Dresden 01069 Germany
| | - Xianjun Zhu
- Hefei National Laboratory for Physical Sciences at Microscale; CAS Key Laboratory of Materials for Energy Conversion; Department of Materials Science and Engineering; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 China
| | - Aram Kostanyan
- Physik-Institut; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Rasmus Westerström
- Physik-Institut; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Fei Jin
- Hefei National Laboratory for Physical Sciences at Microscale; CAS Key Laboratory of Materials for Energy Conversion; Department of Materials Science and Engineering; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 China
| | - Su-Yuan Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials); College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
| | - Alexey A. Popov
- Leibniz Institute for Solid State and Materials Research Dresden; Helmholtzstrasse 20 Dresden 01069 Germany
| | - Thomas Greber
- Physik-Institut; Universität Zürich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Shangfeng Yang
- Hefei National Laboratory for Physical Sciences at Microscale; CAS Key Laboratory of Materials for Energy Conversion; Department of Materials Science and Engineering; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 China
| |
Collapse
|
12
|
Liu F, Wang S, Gao CL, Deng Q, Zhu X, Kostanyan A, Westerström R, Jin F, Xie SY, Popov AA, Greber T, Yang S. Mononuclear Clusterfullerene Single-Molecule Magnet Containing Strained Fused-Pentagons Stabilized by a Nearly Linear Metal Cyanide Cluster. Angew Chem Int Ed Engl 2017; 56:1830-1834. [PMID: 28079303 PMCID: PMC5295638 DOI: 10.1002/anie.201611345] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Indexed: 11/10/2022]
Abstract
Fused-pentagons results in an increase of local steric strain according to the isolated pentagon rule (IPR), and for all reported non-IPR clusterfullerenes multiple (two or three) metals are required to stabilize the strained fused-pentagons, making it difficult to access the single-atom properties. Herein, we report the syntheses and isolations of novel non-IPR mononuclear clusterfullerenes MNC@C76 (M=Tb, Y), in which one pair of strained fused-pentagon is stabilized by a mononuclear cluster. The molecular structures of MNC@C76 (M=Tb, Y) were determined unambiguously by single-crystal X-ray diffraction, featuring a non-IPR C2v (19138)-C76 cage entrapping a nearly linear MNC cluster, which is remarkably different from the triangular MNC cluster within the reported analogous clusterfullerenes based on IPR-obeying C82 cages. The TbNC@C76 molecule is found to be a field-induced single-molecule magnet (SMM).
Collapse
Affiliation(s)
- Fupin Liu
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Song Wang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Cong-Li Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Qingming Deng
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstrasse 20, Dresden, 01069, Germany
| | - Xianjun Zhu
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Aram Kostanyan
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Rasmus Westerström
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Fei Jin
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Su-Yuan Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstrasse 20, Dresden, 01069, Germany
| | - Thomas Greber
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Shangfeng Yang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
| |
Collapse
|
13
|
Zanin DA, De Pietro LG, Peter Q, Kostanyan A, Cabrera H, Vindigni A, Bähler T, Pescia D, Ramsperger U. Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy. Proc Math Phys Eng Sci 2016; 472:20160475. [PMID: 27956876 PMCID: PMC5134307 DOI: 10.1098/rspa.2016.0475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We perform scanning tunnelling microscopy (STM) in a regime where primary electrons are field-emitted from the tip and excite secondary electrons out of the target—the scanning field-emission microscopy regime (SFM). In the SFM mode, a secondary-electron contrast as high as 30% is observed when imaging a monoatomic step between a clean W(110)- and an Fe-covered W(110)-terrace. This is a figure of contrast comparable to STM. The apparent width of the monoatomic step attains the 1 nm mark, i.e. it is only marginally worse than the corresponding width observed in STM. The origin of the unexpected strong contrast in SFM is the material dependence of the secondary-electron yield and not the dependence of the transported current on the tip–target distance, typical of STM: accordingly, we expect that a technology combining STM and SFM will highlight complementary aspects of a surface while simultaneously making electrons, selected with nanometre spatial precision, available to a macroscopic environment for further processing.
Collapse
Affiliation(s)
- D A Zanin
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - L G De Pietro
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - Q Peter
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - A Kostanyan
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - H Cabrera
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - A Vindigni
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - Th Bähler
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - D Pescia
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| | - U Ramsperger
- Laboratory for Solid State Physics , ETH Zurich , 8093 Zurich, Switzerland
| |
Collapse
|
14
|
Liu F, Gao CL, Deng Q, Zhu X, Kostanyan A, Westerström R, Wang S, Tan YZ, Tao J, Xie SY, Popov AA, Greber T, Yang S. Triangular Monometallic Cyanide Cluster Entrapped in Carbon Cage with Geometry-Dependent Molecular Magnetism. J Am Chem Soc 2016; 138:14764-14771. [PMID: 27755875 DOI: 10.1021/jacs.6b09329] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clusterfullerenes are capable of entrapping a variety of metal clusters within carbon cage, for which the entrapped metal cluster generally keeps its geometric structure (e.g., bond distance and angle) upon changing the isomeric structure of fullerene cage, and whether the properties of the entrapped metal cluster is geometry-dependent remains unclear. Herein we report an unusual triangular monometallic cluster entrapped in fullerene cage by isolating several novel terbium cyanide clusterfullerenes (TbNC@C82) with different cage isomeric structures. Upon varying the isomeric structure of C82 cage from C2(5) to Cs(6) and to C2v(9), the entrapped triangular TbNC cluster exhibits significant distortions as evidenced by the changes of Tb-C(N) and C-N bond distances and variation of the Tb-C(N)-N(C) angle by up to 20°, revealing that the geometric structure of the entrapped triangular TbNC cluster is variable. All three TbNC@C82 molecules are found to be single-ion magnets, and the change of the geometric structure of TbNC cluster directly leads to the alternation of the magnetic relaxation time of the corresponding TbNC@C82 clusterfullerene.
Collapse
Affiliation(s)
- Fupin Liu
- Hefei National Laboratory for Physical Sciences at Microscale, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China (USTC) , Hefei 230026, China
| | - Cong-Li Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China
| | - Qingming Deng
- Leibniz Institute for Solid State and Materials Research Dresden , Helmholtzstrasse 20, Dresden 01069, Germany
| | - Xianjun Zhu
- Hefei National Laboratory for Physical Sciences at Microscale, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China (USTC) , Hefei 230026, China
| | - Aram Kostanyan
- Physik-Institut, Universität Zürich , Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Rasmus Westerström
- Physik-Institut, Universität Zürich , Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Song Wang
- Hefei National Laboratory for Physical Sciences at Microscale, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China (USTC) , Hefei 230026, China
| | - Yuan-Zhi Tan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China
| | - Jun Tao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China
| | - Su-Yuan Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research Dresden , Helmholtzstrasse 20, Dresden 01069, Germany
| | - Thomas Greber
- Physik-Institut, Universität Zürich , Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Shangfeng Yang
- Hefei National Laboratory for Physical Sciences at Microscale, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China (USTC) , Hefei 230026, China
| |
Collapse
|
15
|
Junghans K, Schlesier C, Kostanyan A, Samoylova NA, Deng Q, Rosenkranz M, Schiemenz S, Westerström R, Greber T, Büchner B, Popov AA. Methan als Selektivitätsverstärker in der Lichtbogensynthese von endohedralen Fullerenen: selektive Synthese des Einzelmolekülmagneten Dy
2
TiC@C
80
und dessen Kongener Dy
2
TiC
2
@C
80. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505870] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Katrin Junghans
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Christin Schlesier
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Aram Kostanyan
- Physik‐Institut der Universität Zürich, 8057 Zürich (Schweiz)
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Schweiz)
| | - Nataliya A. Samoylova
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Qingming Deng
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Marco Rosenkranz
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Sandra Schiemenz
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | | | - Thomas Greber
- Physik‐Institut der Universität Zürich, 8057 Zürich (Schweiz)
| | - Bernd Büchner
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| | - Alexey A. Popov
- Leibniz‐Institut für Festkörper‐ und Werkstoffforschung, Helmholtzstraße 20, 01069 Dresden (Deutschland)
| |
Collapse
|
16
|
Junghans K, Schlesier C, Kostanyan A, Samoylova NA, Deng Q, Rosenkranz M, Schiemenz S, Westerström R, Greber T, Büchner B, Popov AA. Methane as a Selectivity Booster in the Arc-Discharge Synthesis of Endohedral Fullerenes: Selective Synthesis of the Single-Molecule Magnet Dy2TiC@C80 and Its Congener Dy2TiC2@C80. Angew Chem Int Ed Engl 2015; 54:13411-5. [PMID: 26350440 PMCID: PMC4902133 DOI: 10.1002/anie.201505870] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Indexed: 11/25/2022]
Abstract
The use of methane as a reactive gas dramatically increases the selectivity of the arc‐discharge synthesis of M‐Ti‐carbide clusterfullerenes (M=Y, Nd, Gd, Dy, Er, Lu). Optimization of the process parameters allows the synthesis of Dy2TiC@C80‐I and its facile isolation in a single chromatographic step. A new type of cluster with an endohedral acetylide unit, M2TiC2@C80, is discovered along with the second isomer of M2TiC@C80. Dy2TiC@C80‐(I,II) and Dy2TiC2@C80‐I are shown to be single‐molecule magnets (SMM), but the presence of the second carbon atom in the cluster Dy2TiC2@C80 leads to substantially poorer SMM properties.
Collapse
Affiliation(s)
- Katrin Junghans
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Christin Schlesier
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Aram Kostanyan
- Physik-Institut der Universität Zürich, 8057 Zürich (Switzerland).,Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)
| | - Nataliya A Samoylova
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Qingming Deng
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Marco Rosenkranz
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Sandra Schiemenz
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | | | - Thomas Greber
- Physik-Institut der Universität Zürich, 8057 Zürich (Switzerland)
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany)
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany).
| |
Collapse
|
17
|
Qasim MM, Khan AA, Kostanyan A, Kidambi PR, Cabrero-Vilatela A, Braeuninger-Weimer P, Gardiner DJ, Hofmann S, Wilkinson TD. Hybrid graphene nematic liquid crystal light scattering device. Nanoscale 2015; 7:14114-14120. [PMID: 26243047 DOI: 10.1039/c5nr04094a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A hybrid graphene nematic liquid crystal (LC) light scattering device is presented. This device exploits the inherent poly-crystallinity of chemical vapour deposited (CVD) graphene films to induce directional anchoring and formation of LC multi-domains. This thereby enables efficient light scattering without the need for crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (< 1 V μm(-1)) and repeatable, hysteresis free characteristics. This exploitation of LC alignment effects on CVD graphene films enables a new generation of highly efficient nematic LC scattering displays as well as many other possible applications.
Collapse
Affiliation(s)
- M M Qasim
- Centre of Molecular Materials for Photonics and Electronics, Department of Engineering, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge, CB3 0FA, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Abstract
The effect of estradiol-17 beta on the activities of glycolytic enzymes from female rat brain was studied. The following enzymes were examined: hexokinase (HK, EC 2.7.1.1), phosphofructokinase (PFK, EC 2.7.1.11), aldolase (EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), phosphoglycerate kinase (EC 2.7.2.3), phosphoglycerate mutase (EC 2.7.5.3), enolase (EC 4.2.1.11) and pyruvate kinase (PK, EC 2.7.1.40). The activities of HK (soluble and membrane-bound), PFK and PK were increased after 4 h of hormone treatment, while the others remained constant. The changes in activity were not seen in the presence of actinomycin D. The significant rise of the activities of the key glycolytic enzymes was also observed in the cell culture of mouse neuroblastoma C1300 treated with hormone. Only three of the studied isozymes, namely, HKII, B4 and K4 were found to be estradiol-sensitive for HK, PFK and PK, respectively. The results obtained suggest that rat brain glycolysis regulation by estradiol is carried out in neurons due to definite isozymes induction.
Collapse
Affiliation(s)
- A Kostanyan
- Institute of Experimental Biology, Armenian Academy of Sciences, Yerevan
| | | |
Collapse
|