Correlation between structural and magnetic properties of half-metallic spinel CuV2S4 due to the order-disorder transition of 3d2(t2g) orbitals of V3+ ions

• Published in: Physica Status Solidi (b) Vol. 245; no. 11; pp. 2539 - 2549
• Main Authors: Kumara, L. S. R., Hidaka, M., Tokiwa, N., Awaka, J., Hagino, T., Nagata, S., Park, Young Jun
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.11.2008; WILEY‐VCH Verlag; Wiley
• Subjects: 64.70.K; 71.45.Lr; 77.80.Bh; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Physics; Solid-solid transitions; Specific phase transitions; Order-disorder transformations; Commensurate phases; Magnetization; Phase transformations; XRD; Magnetic transitions; Magnetic susceptibility; Weak ferromagnetism; Spinels; Superlattices; Superstructure; Semimetals; Copper Vanadium Sulfides Mixed; Property structure relationship; Synchrotron radiation
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200743485

Structural and magnetic properties of the spinel CuV2S4 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 ± qo, k ± qo, l) having an orthorhombic reduced wavevector qo = (1/4, 1/4, 0) are observed at 10 K. This suggests that the structure below 55 K is a commensurate unit cell of 4ap × 4bp × cp, 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 VS6 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 CuV2S4 in the low‐temperature phases below about 90 K are interpreted by order and disorder states of (3dxy, 3dyz, 3dzx) for the V3+ 3d2(t2g) orbitals in the VS6 octahedral chains. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)