Structural modulation induced by the incommensurate antiferromagnetic phase transition in ZnCr2Se4

• Published in: Physica Status Solidi (b) Vol. 236; no. 3; pp. 570 - 577
• Main Authors: HIDAKA, M, YOSHIMURA, M, TOKIWA, N, AKIMITSU, J, YONG JUN PARK, JAE HYUN PARK, SUNG DAE JI, KI BONG LEE
• Format: Journal Article
• Language: English
• Published: Berlin Wiley 01.04.2003
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystalline state (including molecular motions in solids); Crystallographic aspects of phase transformations; pressure effects; Exact sciences and technology; Magnetic properties and materials; Magnetomechanical and magnetoelectric effects, magnetostriction; Physics; Structure of solids and liquids; crystallography; Antiferromagnetism; Temperature dependence; Cubic lattices; Inorganic compounds; Chromium selenides; Magnetostriction; Incommensurate phases; Phase transformations; Ternary compounds; Transition element compounds; Modulated structure; Zinc selenides; Crystal field; XRD; Experimental study; Spinels; Orthorhombic lattices; Synchrotron radiation
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200301551

The structural properties of normal-type spinel ZnCr2Se4 have been studied as a function of temperature by means of X-ray diffraction using synchrotron radiation. It is found that a structural phase transition from cubic to orthorhombic symmetry occurs at 22.5 K (Tc). It is also found that, below Tc, Se ions are cooperatively displaced in a pseudo-tetragonal (001) plane. Since the Cr3+ ion has no orbital angular momentum, a CrSe6 octahedron is not distorted by a crystal field produced by surrounding Se2- anions. It is interpreted that the pseudo-tetragonal displacements of Se ions are induced by magnetostriction among Cr3+ ions in CrSe2 chains, in which Cr ions share two Se2- with each other along < 110 > .