1
|
Li B, Ye X, Wang X, Zhang J, Lu D, Zhao H, Pi M, Hu Z, Lin HJ, Chen CT, Pan Z, Qin X, Long Y. High-Pressure-Stabilized Post-Spinel Phase of CdFe 2O 4 with Distinct Magnetism from Its Ambient-Pressure Spinel Phase. Inorg Chem 2023. [PMID: 37256851 DOI: 10.1021/acs.inorgchem.3c01002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
α-CdFe2O4 stabilizes its normal spinel structure due to the covalent Cd-O bond, in which all the connections between adjacent FeO6 octahedral are edge-shared, forming a typical geometrically frustrated Fe3+ magnetic lattice. As the high-pressure methods were utilized, the post-spinel phase β-CdFe2O4 with a CaFe2O4-type structure was synthesized at 8 GPa and 1373 K. The new polymorph has an orthorhombic structure with the space group Pnma and an 11.5% higher density than that of its normal spinel polymorph (α-CdFe2O4) synthesized at ambient conditions. The edge-shared FeO6 octahedra form zigzag S = 5/2 spin ladders along the b-axis dominating its low-dimensional magnetic properties at high temperatures and a long-range antiferromagnetic ordering with a high Néel temperature of TN1 = 350 K. Further, the rearrangement of magnetic ordering was found to occur around TN2 = 265 K, below which the competition of two phases or several couplings induce complex antiferromagnetic behaviors.
Collapse
Affiliation(s)
- Beihong Li
- Department of Physics, Shanghai Normal University, Shanghai 200234, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xubin Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dabiao Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haoting Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maocai Pi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Hu
- Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Zhao Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaomei Qin
- Department of Physics, Shanghai Normal University, Shanghai 200234, China
| | - Youwen Long
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| |
Collapse
|
2
|
Songvilay M, Petit S, Damay F, Roux G, Qureshi N, Walker HC, Rodriguez-Rivera JA, Gao B, Cheong SW, Stock C. From One- to Two-Magnon Excitations in the S=3/2 Magnet β-CaCr_{2}O_{4}. PHYSICAL REVIEW LETTERS 2021; 126:017201. [PMID: 33480800 DOI: 10.1103/physrevlett.126.017201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/14/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
We apply neutron spectroscopy to measure the magnetic dynamics in the S=3/2 magnet β-CaCr_{2}O_{4} (T_{N}=21 K). The low-energy fluctuations, in the ordered state, resemble large-S linear spin waves from the incommensurate ground state. However, at higher energy transfers, these semiclassical and harmonic dynamics are replaced by an energy and momentum broadened continuum of excitations. Applying kinematic constraints required for energy and momentum conservation, sum rules of neutron scattering, and comparison against exact diagonalization calculations, we show that the dynamics at high-energy transfers resemble low-S one-dimensional quantum fluctuations. β-CaCr_{2}O_{4} represents an example of a magnet at the border between classical Néel and quantum phases, displaying dual characteristics.
Collapse
Affiliation(s)
- M Songvilay
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - S Petit
- Laboratoire Léon Brillouin, CEA-CNRS UMR 12, 91191 Gif-Sur-Yvette Cedex, France
| | - F Damay
- Laboratoire Léon Brillouin, CEA-CNRS UMR 12, 91191 Gif-Sur-Yvette Cedex, France
| | - G Roux
- Université Paris-Saclay, CNRS, LPTMS, 91405 Orsay, France
| | - N Qureshi
- Institut Laue-Langevin, 6 rue Jules Horowitz, Boite postale 156, 38042 Grenoble, France
| | - H C Walker
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - B Gao
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - C Stock
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| |
Collapse
|
3
|
Ewings RA, Stewart JR, Perring TG, Bewley RI, Le MD, Raspino D, Pooley DE, Škoro G, Waller SP, Zacek D, Smith CA, Riehl-Shaw RC. Upgrade to the MAPS neutron time-of-flight chopper spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:035110. [PMID: 30927771 DOI: 10.1063/1.5086255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/01/2019] [Indexed: 05/23/2023]
Abstract
The MAPS direct geometry time-of-flight chopper spectrometer at the ISIS pulsed neutron and muon source has been in operation since 1999, and its novel use of a large array of position-sensitive neutron detectors paved the way for a later generations of chopper spectrometers around the world. Almost two decades of experience of user operations on MAPS, together with lessons learned from the operation of new generation instruments, led to a decision to perform three parallel upgrades to the instrument. These were to replace the primary beamline collimation with supermirror neutron guides, to install a disk chopper, and to modify the geometry of the poisoning in the water moderator viewed by MAPS. Together, these upgrades were expected to increase the neutron flux substantially, to allow more flexible use of repetition rate multiplication and to reduce some sources of background. Here, we report the details of these upgrades and compare the performance of the instrument before and after their installation as well as to Monte Carlo simulations. These illustrate that the instrument is performing in line with, and in some respects in excess of, expectations. It is anticipated that the improvement in performance will have a significant impact on the capabilities of the instrument. A few examples of scientific commissioning are presented to illustrate some of the possibilities.
Collapse
Affiliation(s)
- R A Ewings
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - J R Stewart
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - T G Perring
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R I Bewley
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - M D Le
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D Raspino
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D E Pooley
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - G Škoro
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - S P Waller
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D Zacek
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - C A Smith
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R C Riehl-Shaw
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| |
Collapse
|
4
|
Prša K, Waldmann O. Inelastic Neutron Scattering Intensities of Ferromagnetic Cluster Spin Waves. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Krunoslav Prša
- Physikalisches Institut Universität Freiburg 79104 Freiburg Germany
| | - Oliver Waldmann
- Physikalisches Institut Universität Freiburg 79104 Freiburg Germany
| |
Collapse
|
5
|
Demmel F, McPhail D, French C, Maxwell D, Harrison S, Boxall J, Rhodes N, Mukhopadhyay S, Silverwood I, Sakai VG, Fernandez-Alonso F. ToF-Backscattering spectroscopy at the ISIS Facility: Status and Perspectives. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1742-6596/1021/1/012027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
6
|
Stock C, Rodriguez EE, Lee N, Demmel F, Fouquet P, Laver M, Niedermayer C, Su Y, Nemkovski K, Green MA, Rodriguez-Rivera JA, Kim JW, Zhang L, Cheong SW. Orphan Spins in the S=5/2 Antiferromagnet CaFe_{2}O_{4}. PHYSICAL REVIEW LETTERS 2017; 119:257204. [PMID: 29303328 DOI: 10.1103/physrevlett.119.257204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Indexed: 06/07/2023]
Abstract
CaFe_{2}O_{4} is an anisotropic S=5/2 antiferromagnet with two competing A (↑↑↓↓) and B (↑↓↑↓) magnetic order parameters separated by static antiphase boundaries at low temperatures. Neutron diffraction and bulk susceptibility measurements, show that the spins near these boundaries are weakly correlated and a carry an uncompensated ferromagnetic moment that can be tuned with a magnetic field. Spectroscopic measurements find these spins are bound with excitation energies less than the bulk magnetic spin waves and resemble the spectra from isolated spin clusters. Localized bound orphaned spins separate the two competing magnetic order parameters in CaFe_{2}O_{4}.
Collapse
Affiliation(s)
- C Stock
- School of Physics and Astronomy and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - E E Rodriguez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - N Lee
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - P Fouquet
- Institute Laue-Langevin, 6 rue Jules Horowitz, Boite Postale 156, 38042 Grenoble Cedex 9, France
| | - M Laver
- School of Metallurgy and Materials, University of Birmingham, B15 2TT, United Kingdom
| | - Ch Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Y Su
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - K Nemkovski
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - M A Green
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - J W Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - L Zhang
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| |
Collapse
|
7
|
Sarte PM, Aczel AA, Ehlers G, Stock C, Gaulin BD, Mauws C, Stone MB, Calder S, Nagler SE, Hollett JW, Zhou HD, Gardner JS, Attfield JP, Wiebe CR. Evidence for the confinement of magnetic monopoles in quantum spin ice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:45LT01. [PMID: 29049030 DOI: 10.1088/1361-648x/aa8ec2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Magnetic monopoles are hypothesised elementary particles connected by Dirac strings that behave like infinitely thin solenoids (Dirac 1931 Proc. R. Soc. A 133 60). Despite decades of searching, free magnetic monopoles and their Dirac strings have eluded experimental detection, although there is substantial evidence for deconfined magnetic monopole quasiparticles in spin ice materials (Castelnovo et al 2008 Nature 326 411). Here we report the detection of a hierarchy of unequally-spaced magnetic excitations via high resolution inelastic neutron spectroscopic measurements on the quantum spin ice candidate [Formula: see text] [Formula: see text] [Formula: see text]. These excitations are well-described by a simple model of monopole pairs bound by a linear potential (Coldea et al Science 327 177) with an effective tension of 0.642(8) K [Formula: see text] at 1.65 K. The success of the linear potential model suggests that these low energy magnetic excitations are direct spectroscopic evidence for the confinement of magnetic monopole quasiparticles in the quantum spin ice candidate [Formula: see text] [Formula: see text] [Formula: see text].
Collapse
Affiliation(s)
- P M Sarte
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom. Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Ming Y, Ling DB, Li HM, Ding ZJ. Energy thresholds of discrete breathers in thermal equilibrium and relaxation processes. CHAOS (WOODBURY, N.Y.) 2017; 27:063106. [PMID: 28679219 DOI: 10.1063/1.4985016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
So far, only the energy thresholds of single discrete breathers in nonlinear Hamiltonian systems have been analytically obtained. In this work, the energy thresholds of discrete breathers in thermal equilibrium and the energy thresholds of long-lived discrete breathers which can remain after a long time relaxation are analytically estimated for nonlinear chains. These energy thresholds are size dependent. The energy thresholds of discrete breathers in thermal equilibrium are the same as the previous analytical results for single discrete breathers. The energy thresholds of long-lived discrete breathers in relaxation processes are different from the previous results for single discrete breathers but agree well with the published numerical results known to us. Because real systems are either in thermal equilibrium or in relaxation processes, the obtained results could be important for experimental detection of discrete breathers.
Collapse
Affiliation(s)
- Yi Ming
- School of Physics and Material Science, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Dong-Bo Ling
- School of Physics and Material Science, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Hui-Min Li
- Supercomputing Center, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Ze-Jun Ding
- Department of Physics and Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| |
Collapse
|
9
|
Gandhi AC, Das R, Chou FC, Lin JG. Magnetocrystalline two-fold symmetry in CaFe 2O 4 single crystal. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:175802. [PMID: 28346220 DOI: 10.1088/1361-648x/aa61f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding of magnetocrystalline anisotropy in CaFe2O4 is a matter of importance for its future applications. A high quality single crystal CaFe2O4 sample is studied by using synchrotron x-ray diffraction, a magnetometer and the electron spin resonance (ESR) technique. A broad feature of the susceptibility curve around room temperature is observed, indicating the development of 1D spin interactions above the on-set of antiferromagnetic transition. The angular dependency of ESR reveals an in-plane two-fold symmetry, suggesting a strong correlation between the room temperature spin structure and magnetocrystalline anisotropy. This finding opens an opportunity for the device utilizing the anisotropy field of CaFe2O4.
Collapse
|