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Shahab Derakhshan - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, Crystal Structure, and Magnetic Properties of Li3Mg2OsO6, a Geometrically Frustrated Osmium(V) Oxide with an Ordered Rock Salt Structure: Comparison with Isostructural Li3Mg2RuO6
2016Co-Authors: Phuong-hieu T. Nguyen, Farshid Ramezanipour, John E. Greedan, Lachlan M. D. Cranswick, Shahab DerakhshanAbstract:The novel osmium-based oxide Li3Mg2OsO6 was synthesized in polycrystalline form by reducing Li5OsO6 by osmium metal and osmium(IV) oxide in the presence of stoichiometric amounts of magnesium oxide. The crystal structure was refined using powder X-ray Diffraction data in the orthorhombic Fddd space group with a = 5.88982(5) Å, b = 8.46873(6) Å, and c = 17.6825(2) Å. This compound is isostructural and isoelectronic with the ruthenium-based system Li3Mg2RuO6. The magnetic ion sublattice Os5+ (S = 3/2) consists of chains of interconnected corner- and edge-shared triangles, which brings about the potential for geometric magnetic frustration. The Curie–Weiss law holds over the range 80–300 K with C = 1.42(3) emu·K/mol [μeff = 3.37(2) μB] and θC = −105.8(2) K. Below 80 K, there are three anomalies at 75, 30, and 8 K. Those at 75 and 30 K are suggestive of short-range antiferromagnetic correlations, while that at 8 K is a somewhat sharper maximum showing a zero-field-cooled/field-cooled divergence suggestive of perhaps spin freezing. The absence of magnetic Bragg peaks at 3.9 K in the Neutron Diffraction Pattern supports this characterization, as does the absence of a sharp peak in the heat capacity, which instead shows only a very broad maximum at ∼12 K. A frustration index of f = 106/8 = 13 indicates a high degree of frustration. The magnetic properties of the osmium phase differ markedly from those of the isostructural ruthenium material, which shows long-range antiferromagnetic order below 17 K, f = 6, and no unusual features at higher temperatures. Estimates of the magnetic exchange interactions at the level of spin-dimer analysis for both the ruthenium and osmium materials support a more frustrated picture for the latter. Errors in the calculation and assignment of the exchange pathways in the previous report on Li3Mg2RuO6 are identified and corrected
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synthesis crystal structure and magnetic properties of li3mg2oso6 a geometrically frustrated osmium v oxide with an ordered rock salt structure comparison with isostructural li3mg2ruo6
Inorganic Chemistry, 2012Co-Authors: Phuonghieu T Nguyen, Farshid Ramezanipour, John E. Greedan, Lachlan M. D. Cranswick, Shahab DerakhshanAbstract:The novel osmium-based oxide Li(3)Mg(2)OsO(6) was synthesized in polycrystalline form by reducing Li(5)OsO(6) by osmium metal and osmium(IV) oxide in the presence of stoichiometric amounts of magnesium oxide. The crystal structure was refined using powder X-ray Diffraction data in the orthorhombic Fddd space group with a = 5.88982(5) A, b = 8.46873(6) A, and c = 17.6825(2) A. This compound is isostructural and isoelectronic with the ruthenium-based system Li(3)Mg(2)RuO(6). The magnetic ion sublattice Os(5+) (S = 3/2) consists of chains of interconnected corner- and edge-shared triangles, which brings about the potential for geometric magnetic frustration. The Curie-Weiss law holds over the range 80-300 K with C = 1.42(3) emu·K/mol [μ(eff) = 3.37(2) μ(B)] and θ(C) = -105.8(2) K. Below 80 K, there are three anomalies at 75, 30, and 8 K. Those at 75 and 30 K are suggestive of short-range antiferromagnetic correlations, while that at 8 K is a somewhat sharper maximum showing a zero-field-cooled/field-cooled divergence suggestive of perhaps spin freezing. The absence of magnetic Bragg peaks at 3.9 K in the Neutron Diffraction Pattern supports this characterization, as does the absence of a sharp peak in the heat capacity, which instead shows only a very broad maximum at ∼12 K. A frustration index of f = 106/8 = 13 indicates a high degree of frustration. The magnetic properties of the osmium phase differ markedly from those of the isostructural ruthenium material, which shows long-range antiferromagnetic order below 17 K, f = 6, and no unusual features at higher temperatures. Estimates of the magnetic exchange interactions at the level of spin-dimer analysis for both the ruthenium and osmium materials support a more frustrated picture for the latter. Errors in the calculation and assignment of the exchange pathways in the previous report on Li(3)Mg(2)RuO(6) are identified and corrected.
B Lake - One of the best experts on this subject based on the ideXlab platform.
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observation of long range magnetic ordering in pyrohafnate nd 2 hf 2 o 7 a Neutron Diffraction study
Physical Review B, 2015Co-Authors: V K Anand, A K Bera, T Herrmannsdorfer, C Ritter, B LakeAbstract:We have investigated the physical properties of a pyrochlore hafnate Nd2Hf2O7 using ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements, and determined the magnetic ground state by Neutron powder Diffraction study. An upturn is observed below 6 K in C_p(T)/T, however both C_p(T) and \chi(T) do not show any clear anomaly down to 2 K. The \chi_ac(T) shows a well pronounced anomaly indicating an antiferromagnetic transition at T_N = 0.55 K. The long range antiferromagnetic ordering is confirmed by Neutron Diffraction. The refinement of Neutron Diffraction Pattern reveals an all-in/all-out antiferromagnetic structure, where for successive tetrahedra, the four Nd3+ magnetic moments point alternatively all-into or all-out-of the tetrahedron, with an ordering wavevector k = (0, 0, 0) and an ordered state magnetic moment of m = 0.62(1) \mu_B/Nd at 0.1 K. The ordered moment is strongly reduced reflecting strong quantum fluctuations in ordered state.
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observation of long range magnetic ordering in pyrohafnate nd2hf2o7 a Neutron Diffraction study
Physical Review B, 2015Co-Authors: V K Anand, Clemens Ritter, A K Bera, T Herrmannsdorfer, J Xu, B LakeAbstract:We have investigated the physical properties of a pyrochlore hafnate Nd2Hf2O7 using ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements, and determined the magnetic ground state by Neutron powder Diffraction study. An upturn is observed below 6 K in C_p(T)/T, however both C_p(T) and \chi(T) do not show any clear anomaly down to 2 K. The \chi_ac(T) shows a well pronounced anomaly indicating an antiferromagnetic transition at T_N = 0.55 K. The long range antiferromagnetic ordering is confirmed by Neutron Diffraction. The refinement of Neutron Diffraction Pattern reveals an all-in/all-out antiferromagnetic structure, where for successive tetrahedra, the four Nd3+ magnetic moments point alternatively all-into or all-out-of the tetrahedron, with an ordering wavevector k = (0, 0, 0) and an ordered state magnetic moment of m = 0.62(1) \mu_B/Nd at 0.1 K. The ordered moment is strongly reduced reflecting strong quantum fluctuations in ordered state.
V K Anand - One of the best experts on this subject based on the ideXlab platform.
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observation of long range magnetic ordering in pyrohafnate nd 2 hf 2 o 7 a Neutron Diffraction study
Physical Review B, 2015Co-Authors: V K Anand, A K Bera, T Herrmannsdorfer, C Ritter, B LakeAbstract:We have investigated the physical properties of a pyrochlore hafnate Nd2Hf2O7 using ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements, and determined the magnetic ground state by Neutron powder Diffraction study. An upturn is observed below 6 K in C_p(T)/T, however both C_p(T) and \chi(T) do not show any clear anomaly down to 2 K. The \chi_ac(T) shows a well pronounced anomaly indicating an antiferromagnetic transition at T_N = 0.55 K. The long range antiferromagnetic ordering is confirmed by Neutron Diffraction. The refinement of Neutron Diffraction Pattern reveals an all-in/all-out antiferromagnetic structure, where for successive tetrahedra, the four Nd3+ magnetic moments point alternatively all-into or all-out-of the tetrahedron, with an ordering wavevector k = (0, 0, 0) and an ordered state magnetic moment of m = 0.62(1) \mu_B/Nd at 0.1 K. The ordered moment is strongly reduced reflecting strong quantum fluctuations in ordered state.
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observation of long range magnetic ordering in pyrohafnate nd2hf2o7 a Neutron Diffraction study
Physical Review B, 2015Co-Authors: V K Anand, Clemens Ritter, A K Bera, T Herrmannsdorfer, J Xu, B LakeAbstract:We have investigated the physical properties of a pyrochlore hafnate Nd2Hf2O7 using ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements, and determined the magnetic ground state by Neutron powder Diffraction study. An upturn is observed below 6 K in C_p(T)/T, however both C_p(T) and \chi(T) do not show any clear anomaly down to 2 K. The \chi_ac(T) shows a well pronounced anomaly indicating an antiferromagnetic transition at T_N = 0.55 K. The long range antiferromagnetic ordering is confirmed by Neutron Diffraction. The refinement of Neutron Diffraction Pattern reveals an all-in/all-out antiferromagnetic structure, where for successive tetrahedra, the four Nd3+ magnetic moments point alternatively all-into or all-out-of the tetrahedron, with an ordering wavevector k = (0, 0, 0) and an ordered state magnetic moment of m = 0.62(1) \mu_B/Nd at 0.1 K. The ordered moment is strongly reduced reflecting strong quantum fluctuations in ordered state.
Clemens Ritter - One of the best experts on this subject based on the ideXlab platform.
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Magnetic structure of Cu2MnBO5 ludwigite: thermodynamic, magnetic properties and Neutron Diffraction study
'IOP Publishing', 2020Co-Authors: Evgeniya Moshkina, Clemens Ritter, Evgeniy Eremin, Svetlana Sofronova, Andrey Kartashev, Andrey Dubrovskiy, Leonard BezmaternykhAbstract:Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.We report on the thermodynamic, magnetic properties and the magnetic structure of ludwigite-type Cu2MnBO5. The specific heat, low-field magnetization and paramagnetic susceptibility were studied on a single crystal and combined with powder Neutron Diffraction data. The temperature dependence of the specific heat and the Neutron Diffraction Pattern reveal a single magnetic phase transition at T = 92 K, which corresponds to the magnetic ordering into a ferrimagnetic phase. The cation distribution and the values and directions of magnetic moments of ions in different crystallographic sites are established. The magnetic moments of Cu2+ and Mn3+ ions occupying different magnetic sites in the ferrimagnetic phase are pairwise antiparallel and their directions do not coincide with the directions of the principal crystallographic axes. The small value of the magnetic moment of copper ions occupying site 2a is indicative of partial disordering of the magnetic moments on this site. The magnetization measurements show a strong temperature hysteresis of magnetization, which evidences for field-dependent transitions below the phase transition temperature
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observation of long range magnetic ordering in pyrohafnate nd2hf2o7 a Neutron Diffraction study
Physical Review B, 2015Co-Authors: V K Anand, Clemens Ritter, A K Bera, T Herrmannsdorfer, J Xu, B LakeAbstract:We have investigated the physical properties of a pyrochlore hafnate Nd2Hf2O7 using ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements, and determined the magnetic ground state by Neutron powder Diffraction study. An upturn is observed below 6 K in C_p(T)/T, however both C_p(T) and \chi(T) do not show any clear anomaly down to 2 K. The \chi_ac(T) shows a well pronounced anomaly indicating an antiferromagnetic transition at T_N = 0.55 K. The long range antiferromagnetic ordering is confirmed by Neutron Diffraction. The refinement of Neutron Diffraction Pattern reveals an all-in/all-out antiferromagnetic structure, where for successive tetrahedra, the four Nd3+ magnetic moments point alternatively all-into or all-out-of the tetrahedron, with an ordering wavevector k = (0, 0, 0) and an ordered state magnetic moment of m = 0.62(1) \mu_B/Nd at 0.1 K. The ordered moment is strongly reduced reflecting strong quantum fluctuations in ordered state.
Phuonghieu T Nguyen - One of the best experts on this subject based on the ideXlab platform.
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synthesis crystal structure and magnetic properties of li3mg2oso6 a geometrically frustrated osmium v oxide with an ordered rock salt structure comparison with isostructural li3mg2ruo6
Inorganic Chemistry, 2012Co-Authors: Phuonghieu T Nguyen, Farshid Ramezanipour, John E. Greedan, Lachlan M. D. Cranswick, Shahab DerakhshanAbstract:The novel osmium-based oxide Li(3)Mg(2)OsO(6) was synthesized in polycrystalline form by reducing Li(5)OsO(6) by osmium metal and osmium(IV) oxide in the presence of stoichiometric amounts of magnesium oxide. The crystal structure was refined using powder X-ray Diffraction data in the orthorhombic Fddd space group with a = 5.88982(5) A, b = 8.46873(6) A, and c = 17.6825(2) A. This compound is isostructural and isoelectronic with the ruthenium-based system Li(3)Mg(2)RuO(6). The magnetic ion sublattice Os(5+) (S = 3/2) consists of chains of interconnected corner- and edge-shared triangles, which brings about the potential for geometric magnetic frustration. The Curie-Weiss law holds over the range 80-300 K with C = 1.42(3) emu·K/mol [μ(eff) = 3.37(2) μ(B)] and θ(C) = -105.8(2) K. Below 80 K, there are three anomalies at 75, 30, and 8 K. Those at 75 and 30 K are suggestive of short-range antiferromagnetic correlations, while that at 8 K is a somewhat sharper maximum showing a zero-field-cooled/field-cooled divergence suggestive of perhaps spin freezing. The absence of magnetic Bragg peaks at 3.9 K in the Neutron Diffraction Pattern supports this characterization, as does the absence of a sharp peak in the heat capacity, which instead shows only a very broad maximum at ∼12 K. A frustration index of f = 106/8 = 13 indicates a high degree of frustration. The magnetic properties of the osmium phase differ markedly from those of the isostructural ruthenium material, which shows long-range antiferromagnetic order below 17 K, f = 6, and no unusual features at higher temperatures. Estimates of the magnetic exchange interactions at the level of spin-dimer analysis for both the ruthenium and osmium materials support a more frustrated picture for the latter. Errors in the calculation and assignment of the exchange pathways in the previous report on Li(3)Mg(2)RuO(6) are identified and corrected.