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Stepanova AV, Mironov AV, Bogach AV, Azarevich AN, Presniakov IA, Sobolev AV, Pankratov DA, Zayakhanov VA, Starchikov SS, Verchenko VY, Shevelkov AV. Bulk ferromagnetism in cleavable van der Waals telluride NbFeTe 2. Chem Commun (Camb) 2024; 60:5518-5521. [PMID: 38693880 DOI: 10.1039/d4cc01160k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
A van der Waals telluride, NbFeTe2, has been synthesized using chemical vapor transport reactions. The optimized synthetic conditions yield high-quality single crystals with a novel monoclinic crystal structure. Monoclinic NbFeTe2 demonstrates a (100) cleavage plane, bulk ferromagnetism below 87 K, and a metallic ground state-the necessary prerequisites for needed spintronics technologies.
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Affiliation(s)
- Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrey N Azarevich
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Igor A Presniakov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
- MSU-BIT University, Shenzhen, 517182 Guangdong Province, P. R. China
| | - Alexey V Sobolev
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
- MSU-BIT University, Shenzhen, 517182 Guangdong Province, P. R. China
| | - Denis A Pankratov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | | | | | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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2
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Kulchu A, Khalaniya RA, Mironov AV, Khrykina ON, Verchenko VY, Stern R, Shevelkov AV. Impact of Ge Doping on Structural and Magnetic Ordering in RMn xGa 3 and R 4Mn 1-xGa 12-yGe y (R = Tb, Dy; x ≤ 0.25, y ≈ 1.0-3.3). Inorg Chem 2023; 62:13348-13361. [PMID: 37549233 DOI: 10.1021/acs.inorgchem.3c01671] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Single crystals of RMnxGa3 and their new quaternary derivatives R4Mn1-xGa12-yGey (R = Tb, Dy, x ≤ 0.25, y ≈ 1.0-3.3) were grown from a Ga flux. The compounds are derivatives of cubic RGa3 phases, with Mn atoms filling the Ga6 voids. RMnxGa3 formally adopts a cubic ABO3 perovskite structure, in which the presence of Mn atoms results in a shift of the neighboring Ga atoms from their ideal position. A partial substitution of Ga by Ge leads to a higher Mn content, resulting in structural ordering of the latter and the formation of the superstructure phases R4Mn1-xGa12-yGey, which can be formally described in the Y4PdGa12 structure type. The presence of Mn vacancies, which was observed for R = Tb, and Ga/Ge mixing lead to a noticeable deviation from the idealized structure. The compounds contain two magnetic sublattices: the R sublattice, which orders antiferromagnetically near 20 K, and the Mn sublattice, which orders ferromagnetically at TC = 125-225 K with the Ge doping resulting in higher TC. The two sublattices are not independent, as the Mn sublattice induces partial ferromagnetic ordering of the rare earth atoms below TC, at least for the Ge-doped phases. Near TN, both magnetic susceptibility and heat capacity reveal complex behavior, indicating changes in magnetic structures below TN.
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Affiliation(s)
- Aleksandr Kulchu
- Faculty of Materials Science, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Roman A Khalaniya
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga N Khrykina
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, 119333 Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Raivo Stern
- National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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3
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Khalaniya RA, Verchenko VY, Bogach AV, Likhanov M, Shevelkov AV. Itinerant ferromagnet Re 4-xMn xGe 7-δ ( x = 0.9-1.5, δ = 0.42-0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure. Dalton Trans 2023. [PMID: 37482916 DOI: 10.1039/d3dt01919e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Re4-xMnxGe7-δ (x = 0.9-1.5, δ = 0.42-0.44) is a new member of the Nowotny chimney-ladder family of compounds and features an incommensurate composite structure of transition element T (Re and Mn) and Ge substructures. Our theoretical calculations indicate metallic conductivity and ferromagnetic ordering, the latter being experimentally observed below 157 K.
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Affiliation(s)
- Roman A Khalaniya
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Alexey V Bogach
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maxim Likhanov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
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4
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Verchenko VY, Kanibolotskiy AV, Chernoukhov IV, Cherednichenko KA, Bogach AV, Znamenkov KO, Sobolev AV, Glazkova IS, Presniakov IA, Shevelkov AV. Layered van der Waals Chalcogenides FeAl 2Se 4, MnAl 2S 4, and MnAl 2Se 4: Atomically Thin Triangular Arrangement of Transition-Metal Atoms. Inorg Chem 2023; 62:7557-7565. [PMID: 37130007 DOI: 10.1021/acs.inorgchem.3c00912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Layered van der Waals (vdW) chalcogenides of 3d transition metals are a rich source of two-dimensional (2D) nanomaterials, in which atomically thin layers with the terminating chalcogen atoms exhibit promising functionality for novel spintronic devices. Here, we report on the synthesis, crystal growth, and magnetic properties of FeAl2Se4, MnAl2S4, and MnAl2Se4 ternary chalcogenides. Crystal structures are probed by powder X-ray diffraction, Mössbauer spectroscopy, and high-resolution transmission electron microscopy. We improve the structural models of FeAl2Se4 and MnAl2S4 and show that isostructural MnAl2S4 and MnAl2Se4 crystallize in the centrosymmetric R3̅̅m space group. In the crystal structure, transition metal and Al atoms mutually occupy the octahedral and tetrahedral voids of four close-packing chalcogen layers terminated by vdW gaps. The transition-metal atoms form a triangular arrangement inside the close-packing layers. As a result, FeAl2Se4 and MnAl2S4 show no long-range magnetic order in the studied temperature range. In the paramagnetic state, Fe and Mn possess effective magnetic moments of 4.99(2) and 5.405(6) μB, respectively. Furthermore, FeAl2Se4 enters a frozen spin-disordered state below 12 K.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Ivan V Chernoukhov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Alexey V Bogach
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - Alexey V Sobolev
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, MSU-BIT University, Shenzhen, Guangdong Province 517182, P. R. China
| | - Iana S Glazkova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, MSU-BIT University, Shenzhen, Guangdong Province 517182, P. R. China
| | - Igor A Presniakov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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5
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Verchenko VY, Stepanova AV, Bogach AV, Kirsanova MA, Shevelkov AV. Cleavable crystals, crystal structure, and magnetic properties of the NbFe 1+xTe 3 layered van der Waals telluride. Dalton Trans 2023; 52:5534-5544. [PMID: 37009650 DOI: 10.1039/d3dt00588g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Transition metal-based two-dimensional nanomaterials with competing magnetic states are at the cutting edge of spintronic and low-power memory devices. In this paper, we present a Fe-rich NbFe1+xTe3 layered telluride (x ≈ 0.5), which shows an interplay of spin-glass and antiferromagnetic states below the Néel temperature of 179 K. The compound has a layered crystal structure, where the NbFeTe3 layers are terminated by the Te atoms and van der Waals gaps. Bulk single crystals grown by chemical vapor transport reactions possess the (1̄01) cleavage plane suitable for the exfoliation of two-dimensional nanomaterials. Combination of high-resolution transmission electron microscopy and powder X-ray diffraction reveals the zigzag ladders of Fe atoms inside the structural layers, as well as complementary zigzag chains of the partially occupied Fe positions in the interstitial region. Fe atoms carry large effective magnetic moment of 4.85(3)μB per atom in the paramagnetic state yielding intriguing magnetic properties of NbFe1+xTe3. They include frozen spin-glass state at low temperatures and spin-flop transition in high magnetic fields indicating promising flexibility of the magnetic system and its potential control by magnetic field or gate tuning in the spintronic devices and heterostructures.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Alexey V Bogach
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maria A Kirsanova
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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6
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Abstract
Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride Fe5AsTe2 can be synthesized by the high-temperature reaction of elements. In the crystal structure, Fe-rich structural layers with the composition of Fe4.58(4)AsTe2 are separated by the van der Waals gaps with no atoms in the interstitial region. Crystal growth employing chemical vapor transport reactions yields bulk cleavable crystals, which exhibit weak inherent ferromagnetism below the Curie temperature of TC = 48 K. In the ordered state, the magnetization shows a dual-slope behavior in low magnetic fields, indicating the compensated or canted nature of magnetism. Magnetic susceptibility and magnetization measurements reveal perpendicular magnetic anisotropy. The large Rhodes-Wohlfarth ratio of 4.6 indicates the itinerant nature of ferromagnetism in Fe5AsTe2.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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7
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Verchenko VY, Kanibolotskiy AV, Bogach AV, Znamenkov KO, Shevelkov AV. Ferromagnetic correlations in the layered van der Waals sulfide FeAl 2S 4. Dalton Trans 2022; 51:8454-8460. [PMID: 35593508 DOI: 10.1039/d2dt00671e] [Citation(s) in RCA: 0] [Impact Index Per Article: 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
Transition metal-based layered compounds with van der Waals gaps between the adjacent layers are a source of two-dimensional (2D) nanomaterials with nontrivial transport and magnetic properties. 2D ferromagnets, both metals and semiconductors, can be leveraged to produce spin-polarized current in spintronic devices with tailored functionalities. Here, we report on the synthesis, crystal growth, crystal and electronic structure, and magnetic properties of the Fe-based FeAl2S4 layered sulfide. In the crystal structure, Fe and Al atoms mix on octahedral and tetrahedral sites between hexagonal layers of S atoms, which are terminated by the van der Waals gaps. Band structure calculations reveal strong electronic correlations within the semiconducting ground state, which induce ferromagnetism with the magnetic moment of 0.12μB per formula unit for a Hubbard interaction U = 5 eV and Hund's rule coupling J = 0.8 eV. Crystal growth employing chemical vapor transport reactions results in bulk cleavable crystals, which show paramagnetic Curie-Weiss behavior at high temperatures with the Fe2+ magnetic centers. At low temperatures, an anomaly is observed on the magnetic susceptibility curve, below which the magnetization shows ferromagnetic hysteresis, indicating the presence of ferromagnetic correlations in FeAl2S4.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia. .,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | | | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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8
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Abstract
Narrow-gap semiconductors are very rare among intermetallic compounds. They appear only when two factors come together: strong hybridization of valence orbitals in the vicinity of the Fermi level and an appropriate number of valence electrons. Surprisingly, the IrIn3 family of intermetallics contains a number of semiconductors, including 17 e- FeGa3, RuGa3, OsGa3, and RuIn3, for which the d-p hybridization gap opens at the Fermi energy. We present comprehensive total energy electronic-structure calculations and crystal orbital Hamilton population analysis of the stable IrIn3-type compounds with semiconducting and metallic properties. The calculated electronic structures possess two pseudogaps and one real gap at the magic valence electron count of 15, 17, and 18 e- per formula unit. When the Fermi level is located in these gaps, the antibonding states are minimized. Total energies calculated for the isomorphous compounds suggest that the metallic state with 18 e- leads to a comparable or even higher thermodynamic stability than the semiconducting state with 17 e-.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
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9
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Likhanov MS, Verchenko VY, Zhupanov VO, Wei Z, Dikarev EV, Kuznetsov AN, Shevelkov AV. Intermetallic Compound Re 2Ga 9Ge with Re- and Ge-Embedded Gallium Clusters: Synthesis, Crystal Structure, Chemical Bonding, and Physical Properties. Inorg Chem 2021; 61:568-578. [PMID: 34932353 DOI: 10.1021/acs.inorgchem.1c03240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transition metal-based endohedral cluster intermetallic compounds are interesting electron phases, which frequently exhibit superconductivity with a peculiar interplay between the critical temperature and valence electron count. We present a new Re-based endohedral gallium cluster compound, Re2Ga9Ge. Its unique crystal structure (P42/mmc space group, a = 8.0452(3) Å, c = 6.7132(2) Å) is built by two types of gallium polyhedra: monocapped Archimedean antiprisms centered by rhenium atoms and tetrahedra containing a main-group element inside. The analysis of chemical bonding shows the presence of localized pairwise interactions between the p-block elements and the formation of multicenter bonds with the participation of d-orbitals of rhenium. In the electronic band structure, the Fermi level is located in a narrow pseudogap indicating the optimum band filling and thus explaining the virtual absence of a homogeneity range. The compound exhibits Pauli paramagnetism and metallic properties with unexpectedly low thermal conductivity. A sharp anomaly observed on the magnetic susceptibility and resistivity curves presumably indicates the electronic phase transition accompanied by charge ordering at the characteristic temperature of T * = 271 K in zero magnetic field.
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Affiliation(s)
- Maxim S Likhanov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Vladislav O Zhupanov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Zheng Wei
- Department of Chemistry, University at Albany, SUNY, Albany, New York 12222, United States
| | - Evgeny V Dikarev
- Department of Chemistry, University at Albany, SUNY, Albany, New York 12222, United States
| | - Alexey N Kuznetsov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,N. S. Kurnakov Institute of General and Inorganic Chemistry RAS, 119991 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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10
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Abstract
When a transition metal combines with an excess of a p-metal, the latter forms endohedral clusters with the number of vertices up to 14. These clusters are the building units of endohedral cluster intermetallic compounds. Although discovered a few decades ago, they have gained renewed interest due to their peculiar crystal and electronic structures and frequently observed superconducting properties. Advances over recent years reveal that endohedral cluster architectures are flexible enough, enabling chemical substitutions and the formation of a series of structurally related phases, where the same clusters can be arranged in different ways. Within the structural series, the superconducting-state parameters, including critical temperature and magnetic field, can be controlled and finely tuned. Herein, we present the most recent results in the chemical properties and superconductivity of endohedral cluster intermetallics and provide an outlook for the field.
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Affiliation(s)
- Valeriy Yu Verchenko
- Lomonosov Moscow State University, Department of Chemistry, 119991 Moscow, Russia. and National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Andrei V Shevelkov
- Lomonosov Moscow State University, Department of Chemistry, 119991 Moscow, Russia.
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11
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Likhanov MS, Verchenko VY, Gippius AA, Zhurenko SV, Tkachev AV, Wei Z, Dikarev EV, Kuznetsov AN, Shevelkov AV. Electron-Precise Semiconducting ReGa 2Ge: Extending the IrIn 3 Structure Type to Group 7 of the Periodic Table. Inorg Chem 2020; 59:12748-12757. [PMID: 32845622 DOI: 10.1021/acs.inorgchem.0c01805] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGa2Ge, a new electron-precise narrow-gap intermetallic semiconductor. The compound crystallizes in the IrIn3 structure type (space group P42/mnm, a = 6.5734(3) Å, c = 6.7450(8) Å, and Z = 4), where Re atoms occupy the Ir site, while Ga and Ge jointly populate the In sites. 69,71Ga nuclear quadrupole resonance spectroscopy indicates nonstatistical partially ordered distribution of Ga and Ge over two available crystallographic sites; however, the Ga:Ge ratio is exactly 2:1 without noticeable homogeneity range. The stoichiometry of ReGa2Ge ensures its precise valence electron count, which is 17 e- per formula unit. Accordingly, a narrow energy gap opens up at the Fermi energy in the electronic structure. Electrical resistivity, Seebeck coefficient, and thermal conductivity are in agreement with the semiconducting behavior deduced from the electronic structure calculations and point to prospective thermoelectric properties at high temperatures. Bonding analysis reveals dominant covalency in Re-E (E = Ga, Ge) and Re-Re interactions.
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Affiliation(s)
- Maxim S Likhanov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,National Institute of Chemical Physics and Biophysics, Tallinn, 12618, Estonia
| | - Andrei A Gippius
- Department of Physics, Lomonosov Moscow State University, Moscow 119991, Russia.,P.N. Lebedev Physics Institute RAS, Moscow 119991, Russia
| | - Sergei V Zhurenko
- Department of Physics, Lomonosov Moscow State University, Moscow 119991, Russia.,P.N. Lebedev Physics Institute RAS, Moscow 119991, Russia
| | | | - Zheng Wei
- Department of Chemistry, University at Albany, SUNY, Albany, New York 12222, United States
| | - Evgeny V Dikarev
- Department of Chemistry, University at Albany, SUNY, Albany, New York 12222, United States
| | - Alexey N Kuznetsov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,N. S. Kurnakov Institute of General and Inorganic Chemistry RAS, Moscow, 119991, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
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12
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Verchenko VY, Zubtsovskii AO, Wei Z, Tsirlin AA, Marcin M, Sobolev AV, Presniakov IA, Dikarev EV, Shevelkov AV. Endohedral Cluster Superconductors in the Mo-Ga-Sn System Explored by the Joint Flux Technique. Inorg Chem 2019; 58:15552-15561. [PMID: 31657910 DOI: 10.1021/acs.inorgchem.9b02598] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Endohedral Ga cluster compounds feature nontrivial superconducting states including the two-gap superconductivity similar in nature to MgB2. We use the joint flux synthetic technique to introduce Sn into the Ga matrix and tune the valence electron count in the two new endohedral cluster superconductors Mo8Ga41-xSnx and Mo4Ga21-x-δSnx with critical temperatures of Tc = 8.7 and 5.85 K, respectively. While the former compound is a derivative of the previously known Mo8Ga41 superconductor, where Sn atoms are enclosed inside the Sn@Ga6 octahedral clusters, the latter is a new architecture built upon Mo@Ga9Sn clusters, Ga@Ga12 cuboctahedra, and Sn4 squares. We show that this novel Mo4Ga21-x-δSnx superconductor features strong electron-phonon coupling with the large ratio of 2Δ(0)/(kBTc) = 4.1 similar to that of the Mo8Ga41 superconductor with the closely related crystal structure.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia.,National Institute of Chemical Physics and Biophysics , 12618 Tallinn , Estonia
| | - Alexander O Zubtsovskii
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia.,Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics , University of Augsburg , 86135 Augsburg , Germany
| | - Zheng Wei
- Department of Chemistry , University at Albany, SUNY , Albany New York 12222 , United States
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics , University of Augsburg , 86135 Augsburg , Germany
| | - Miroslav Marcin
- Institute of Experimental Physics , Slovak Academy of Sciences , 04001 Košice , Slovakia
| | - Alexey V Sobolev
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia
| | - Igor A Presniakov
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia
| | - Evgeny V Dikarev
- Department of Chemistry , University at Albany, SUNY , Albany New York 12222 , United States
| | - Andrei V Shevelkov
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia
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13
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Marcin M, Kačmarčík J, Pribulová Z, Kopčík M, Szabó P, Šofranko O, Samuely T, Vaňo V, Marcenat C, Verchenko VY, Shevelkov AV, Samuely P. Single-gap superconductivity in Mo 8Ga 41. Sci Rep 2019; 9:13552. [PMID: 31537828 PMCID: PMC6753155 DOI: 10.1038/s41598-019-49846-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 05/23/2019] [Accepted: 08/28/2019] [Indexed: 11/09/2022] Open
Abstract
In this paper, the potential existence of two-gap superconductivity in Mo8Ga41 is addressed in detail by means of thermodynamic and spectroscopic measurements. A combination of highly sensitive bulk and surface probes, specifically ac-calorimetry and scanning tunneling spectroscopy (STS), are utilized on the same piece of crystal and reveal the presence of only one intrinsic gap in the system featuring strong electron-phonon coupling. Minute traces of additional superconducting phases detected by STS and also in the heat capacity measured in high magnetic fields on a high-quality and seemingly single-phase crystal might mimic the multigap superconductivity of Mo8Ga41 suggested recently in several studies.
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Affiliation(s)
- Miroslav Marcin
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Jozef Kačmarčík
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Zuzana Pribulová
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia.
| | - Michal Kopčík
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Pavol Szabó
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Ondrej Šofranko
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Tomáš Samuely
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
| | - Viliam Vaňo
- Faculty of Electrical Engineering and Informatics, Department of Physics, Technical University, SK-04001, Košice, Slovakia
| | | | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991, Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618, Tallinn, Estonia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Peter Samuely
- Centre of Low Temperature Physics, Institute of Experimental Physics SAS, and Faculty of Science, P. J. Šafárik University, 040 01, Košice, Slovakia
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14
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Verchenko VY, Zubtsovskii AO, Wei Z, Tsirlin AA, Dikarev EV, Shevelkov AV. From endohedral cluster superconductors to approximant phases: synthesis, crystal and electronic structure, and physical properties of Mo 8Ga 41-xZn x and Mo 7Ga 52-xZn x. Dalton Trans 2019; 48:7853-7861. [PMID: 31073584 DOI: 10.1039/c8dt04982c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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
Using the crystal-growth joint flux technique based on the combination of two aliovalent low-melt metals, gallium and zinc, we adjust the gross valence electron count in the Mo-Ga-Zn system and produce the Mo8Ga41-xZnx and Mo7Ga52-xZnx intermetallic compounds. Gradual reduction in the valence electron count first leads to the Zn for Ga substitution in the Mo8Ga41 endohedral cluster superconductor, accompanied by the formation of Zn-containing clusters in the crystal structure and by the gradual suppression of superconductivity. Mo8Ga41-xZnx with x = 7.2(2) exhibits superconducting properties below TC = 4 K, whereas there is no superconducting transition at temperatures above 2 K for the limiting composition of x = 11.3(2). Further, the Mo7Ga52-xZnx phase is formed from the flux with a higher content of Zn. Mo7Ga52-xZnx crystallizes in the Mo7Sn12Zn40 structure type with a narrow homogeneity range and exhibits metallic behavior with no sign of superconductivity down to at least 1.8 K. Its experimental valence electron count of 2.9 e per atom is below that of endohedral gallium cluster superconductors. Electronic structures of Mo8Ga41-xZnx and Mo7Ga52-xZnx feature the opening of a pseudogap slightly below the Fermi level indicating the specific stability of these structure types at the valence electron count of 3.2 e per atom and 2.7 e per atom, respectively.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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15
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Likhanov MS, Khalaniya RA, Verchenko VY, Gippius AA, Zhurenko SV, Tkachev AV, Fazlizhanova DI, Kuznetsov AN, Shevelkov AV. ReGaGe 2: an intermetallic compound with semiconducting properties and localized bonding. Chem Commun (Camb) 2019; 55:5821-5824. [PMID: 31041961 DOI: 10.1039/c9cc02563d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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
ReGaGe2 is a new member of the family of intermetallic compounds with non-metallic properties. It displays highly localized covalent bonding patterns. Its electronic structure is governed by mixing of Re d orbitals with the s and p orbitals of Ga and Ge and features the Fermi level falling into the opened band gap, ensuring experimentally confirmed semiconducting properties.
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Affiliation(s)
- Maxim S Likhanov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
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16
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Likhanov MS, Verchenko VY, Kuznetsov AN, Shevelkov AV. ReGa 0.4Ge 0.6: Intermetallic Compound with Pronounced Covalency in the Bonding Pattern. Inorg Chem 2019; 58:2822-2832. [PMID: 30720267 DOI: 10.1021/acs.inorgchem.8b03468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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
We report synthesis, crystal and electronic structure, and transport properties of new intermetallic compound ReGa0.4Ge0.6, which was obtained by two-step ampule method from the elements. ReGa0.4Ge0.6 crystallizes in its own structure type (space group I4/ mmm, a = 2.89222(3) Å, c = 15.1663(3) Å, and Z = 4) which can be described as a sequential alternation of blocks of rhenium atoms and blocks of gallium and germanium atoms. Chemical bonding analysis reveals pronounced covalency of Re-Re, Re-E, and E-E (E = Ga and Ge) interactions and an interesting bonding pattern that includes many variations of localized bonding within a single compound, including pairwise homo- and heterometallic bonding, three-centered homometallic and four-centered bonding, and possibly even more delocalized bonding, which is not often encountered in such a simple intermetallic compound. Metallic behavior is confirmed by electronic structure calculations and by measurements of electrical resistivity.
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Affiliation(s)
- Maxim S Likhanov
- Department of Chemistry , Lomonosov Moscow State University , Moscow 119991 , Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry , Lomonosov Moscow State University , Moscow 119991 , Russia.,National Institute for Chemical Physics and Biophysics , Tallinn 12618 , Estonia
| | - Alexey N Kuznetsov
- Department of Chemistry , Lomonosov Moscow State University , Moscow 119991 , Russia.,N. S. Kurnakov Institute of General and Inorganic Chemistry, RAS , Moscow 119991 , Russia
| | - Andrei V Shevelkov
- Department of Chemistry , Lomonosov Moscow State University , Moscow 119991 , Russia
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17
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Verchenko VY, Mironov AV, Wei Z, Tsirlin AA, Dikarev EV, Shevelkov AV. Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count. Inorg Chem 2019; 58:1561-1570. [PMID: 30615431 DOI: 10.1021/acs.inorgchem.8b03083] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this study, we modify the flux-growth method for the purpose of exploratory synthesis of ternary intermetallic compounds. Our concept is based on the assumption that valence electron count plays a crucial role in the stability of polar intermetallic compounds of different structure types. Control of the valence electron count parameter is made possible through the use of an excess of two metals having a different number of valence electrons. By gradually changing the ratio between these metals in the joint flux, we scan the gross number of valence electrons and explore the crystallization of new compounds. In the ternary system Re-Ga-Zn, we detect compounds belonging to three structure types, ReGa5, PtHg4, and V8Ga41, while gradually increasing the content of Zn metal in the flux. Two new compounds, ReGa3Zn and Re8Ga41- xZn x with x = 21.2(5), are obtained in the form of high-quality single crystals, and the former compound shows the narrow-gap semiconducting behavior favorable for high thermoelectric performance.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia.,National Institute of Chemical Physics and Biophysics , 12618 Tallinn , Estonia
| | - Andrei V Mironov
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia
| | - Zheng Wei
- Department of Chemistry , University at Albany, SUNY , Albany , New York 12222 , United States
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics , University of Augsburg , 86135 Augsburg , Germany
| | - Evgeny V Dikarev
- Department of Chemistry , University at Albany, SUNY , Albany , New York 12222 , United States
| | - Andrei V Shevelkov
- Department of Chemistry , Lomonosov Moscow State University , 119991 Moscow , Russia
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18
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Badrtdinov DI, Kuznetsova ES, Verchenko VY, Berdonosov PS, Dolgikh VA, Mazurenko VV, Tsirlin AA. Magnetism of coupled spin tetrahedra in ilinskite-type KCu 5O 2(SeO 3) 2Cl 3. Sci Rep 2018; 8:2379. [PMID: 29402893 PMCID: PMC5799366 DOI: 10.1038/s41598-018-20350-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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: 10/13/2017] [Accepted: 01/15/2018] [Indexed: 11/08/2022] Open
Abstract
Synthesis, thermodynamic properties, and microscopic magnetic model of ilinskite-type KCu5O2(SeO3)2Cl3 built by corner-sharing Cu4 tetrahedra are reported, and relevant magnetostructural correlations are discussed. Quasi-one-dimensional magnetic behavior with the short-range order around 50 K is rationalized in terms of weakly coupled spin ladders (tubes) having a complex topology formed upon fragmentation of the tetrahedral network. This fragmentation is rooted in the non-trivial effect of the SeO3 groups that render the Cu-O-Cu superexchange strongly ferromagnetic even at bridging angles exceeding 110°.
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Affiliation(s)
- Danis I Badrtdinov
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, 620002, Ekaterinburg, Russia.
| | - Elena S Kuznetsova
- Department of Chemistry, Moscow State University, 119991, Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Moscow State University, 119991, Moscow, Russia
- National Institute of Chemical Physics and Biophysics, 12618, Tallinn, Estonia
| | - Peter S Berdonosov
- Department of Chemistry, Moscow State University, 119991, Moscow, Russia
| | - Valeriy A Dolgikh
- Department of Chemistry, Moscow State University, 119991, Moscow, Russia
| | - Vladimir V Mazurenko
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, 620002, Ekaterinburg, Russia
| | - Alexander A Tsirlin
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, 620002, Ekaterinburg, Russia.
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135, Augsburg, Germany.
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19
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Khalaniya RA, Mironov AV, Verchenko VY, Jesche A, Tsirlin AA, Shevelkov AV. Nontrivial Recurrent Intergrowth Structure and Unusual Magnetic Behavior of Intermetallic Compound Fe 32+δGe 33As 2. Inorg Chem 2016; 55:12953-12961. [PMID: 27989149 DOI: 10.1021/acs.inorgchem.6b02412] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new phase Fe32+δGe33As2 (δ ≤ 0.136) was obtained by two-step synthesis from the elements. Fe32+δGe33As2 crystallizes in its own structure type (space group P6/mmm, Z = 1, a = 11.919(3) Å, c = 7.558(4) Å) that can be described as a recurrent two-dimensional intergrowth of two intermetallic structure types, MgFe6Ge6 and Co2Al5. Their blocks are represented by infinite columns in the structure. No visible structural changes were observed in the temperature range from 10 to 300 K. At 125 K, Fe32+δGe33As2 undergoes an antiferromagnetic-like transition, while above 150 K it shows a typical Curie-Weiss paramagnetic behavior. Below the transition temperature, a peculiar field-dependent magnetic susceptibility, that shows a significant increase of the susceptibility upon increasing the magnetic field, and a change in transport properties have been observed. Above 140 K, Fe32+δGe33As2 reveals a metallic behavior, in agreement with electronic structure calculation, while below this point the resistivity nonmonotonically increases upon cooling. The Seebeck coefficient is positive, indicating that holes are the major charge carriers, and shows a broad maximum around 57 K.
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Affiliation(s)
- Roman A Khalaniya
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics , 12618 Tallinn, Estonia
| | - Anton Jesche
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg , 86135 Augsburg, Germany
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg , 86135 Augsburg, Germany
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
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20
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Plokhikh IV, Charkin DO, Verchenko VY, Kuznetsov AN, Kazakov SM, Tsirlin AA, Shevelkov AV. Structural and Thermodynamic Stability of the "1111" Structure Type: A Case Study of the EuFZnPn Series. Inorg Chem 2016; 55:12409-12418. [PMID: 27934435 DOI: 10.1021/acs.inorgchem.6b02297] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two new compounds with the LaOAgS structure, EuFZnAs (1) and EuFZnSb (2), were obtained via solid state reaction. Both compounds are tetragonal (P4/nmm) with the cell parameters a = 4.1000(1) Å and c = 9.0811(1) Å for 1 and a = 4.2852(1)Å and c = 9.4238(1)Å for 2. The absence of their phosphide analog can be explained based on crystal chemical considerations as well as on quantum-chemical estimates of their thermodynamic stability with respect to EuF2 and EuZn2Pn2. The magnetic response of 1 and 2 is ascribed to the presence of Eu2+ ions. Both compounds are paramagnetic down to low temperatures, where they order antiferromagnetically at ∼5 K and ∼3 K, respectively. They are narrow-gap semiconductors, and EuFZnSb demonstrates a relatively high value of the Seebeck coefficient.
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Affiliation(s)
- Igor V Plokhikh
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Dmitri O Charkin
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics , 12618 Tallinn, Estonia
| | - Alexey N Kuznetsov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia.,N.S. Kurnakov Institute of General and Inorganic Chemistry RAS , 119991 Moscow, Russia
| | - Sergey M Kazakov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Correlations and Magnetism, Institute of Physics, University of Augsburg , 86135 Augsburg, Germany
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University , 119991 Moscow, Russia
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21
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Verchenko VY, Sokolov SS, Tsirlin AA, Sobolev AV, Presniakov IA, Bykov MA, Kirsanova MA, Shevelkov AV. New Fe-based layered telluride Fe 3-δAs 1-yTe 2: synthesis, crystal structure and physical properties. Dalton Trans 2016; 45:16938-16947. [PMID: 27722484 DOI: 10.1039/c6dt02721k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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
A new ternary telluride, Fe3-δAs1-yTe2, was synthesized from elements at 600 °C. It crystallizes in the hexagonal P63/mmc space group with the unit cell parameters a = 3.85091(9) Å and c = 17.1367(4) Å for δ = 0.3 and y = 0.04. Its layered crystal structure contains partially occupied intralayer and interlayer Fe positions, which give rise to significant nonstoichiometry: Fe3-δAs1-yTe2 was found to possess the homogeneity range of 0.25 < δ < 0.45 and y = 0.04. Regions of local vacancy ordering alternate with regions of randomly distributed vacancies, so that the ordering of Fe atoms and vacancies is not complete in the average structure. Clear evidence of the magnetic phase transition is obtained by thermodynamic measurements, Mössbauer spectroscopy, and neutron powder diffraction. Magnetic susceptibility measurements reveal weak ferromagnetism below TC = 123 K with a net moment of MS∼ 0.1μB/Fe at T = 2 K. This transition is confirmed by differential scanning calorimetry. Additionally, neutron powder diffraction indicates the onset of a complex AFM-like magnetic ordering below 100 K.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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