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Correlation between structural and magnetic properties of half‐metallic spinel CuV 2 S 4 due to the order–disorder transition of 3d 2 (t 2g ) orbitals of V 3+ ions
Author(s) -
Kumara L. S. R.,
Hidaka M.,
Tokiwa N.,
Awaka J.,
Hagino T.,
Nagata S.,
Park Young Jun
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200743485
Subject(s) - orthorhombic crystal system , spinel , crystallography , magnetic susceptibility , octahedron , superlattice , ferromagnetism , chemistry , condensed matter physics , materials science , crystal structure , physics , metallurgy
Structural and magnetic properties of the spinel CuV 2 S 4 have been studied by means of X‐ray diffraction using synchrotron radiation and measurements of magnetic susceptibility. The structural phase transitions occur at about 55 K and 90 K, and the superlattice reflections ( h ± q o , k ± q o , l ) having an orthorhombic reduced wavevector q o = (1/4, 1/4, 0) are observed at 10 K. This suggests that the structure below 55 K is a commensurate unit cell of 4 a p × 4 b p × c p , where the subscript ‘p’ means a pseudo‐spinel structure, and that the structural phase transitions are induced by the cooperative displacement of S ions in one‐dimensional VS 6 octahedral chains, which are aligned along an orthorhombic [110] direction. The susceptibility also shows that the weak ferromagnetic transition occurs at about 90 K, and the spike‐like susceptibility is observed in the region of about 40 K and 55 K. The unusual electronic and magnetic properties of CuV 2 S 4 in the low‐temperature phases below about 90 K are interpreted by order and disorder states of (3d xy , 3d yz , 3d zx ) for the V 3+ 3d 2 (t 2g ) orbitals in the VS 6 octahedral chains. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)