Correlation between the structural and antiferromagnetic phase transitions in ZnCr2Se4

• Published in: Physica Status Solidi (b) Vol. 236; no. 1; pp. 9 - 18
• Main Authors: Hidaka, M., Tokiwa, N., Fujii, M., Watanabe, S., Akimitsu, J.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.03.2003; WILEY‐VCH Verlag; Wiley
• Subjects: 61.12.Ld; 61.50.Ks; 64.70.Kb; 75.30.Kz; 75.80.+q; 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 phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetomechanical and magnetoelectric effects, magnetostriction; Neutron diffraction and scattering; Physics; Single-crystal and powder diffraction; Structure of solids and liquids; crystallography; Antiferromagnetism; Temperature dependence; Cubic lattices; Inorganic compounds; Chromium selenides; Magnetostriction; Incommensurate phases; Phase transformations; Neutron diffraction; Ternary compounds; Transition element compounds; Long-range order; Zinc selenides; Experimental study; Monocrystals; Spinels; Orthorhombic lattices; Magnetic structure; Exchange interactions
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200301502

Structural properties of normal‐type spinel ZnCr2Se4 have been studied as a function of temperature by means of neutron diffraction. It is found that the structural phase transition (TC) from a cubic to orthorhombic symmetry simultaneously occurs at the antiferromagnetic phase transition temperature (TN ∼ 21 K), where the cubic and orthorhombic symmetry is 7Oh‐Fd3m and 24D2h‐Fddd, respectively. The structural phase transition is mainly characterized by the cooperative displacements of Se2– ions, which are induced by a magnetostriction resulting from the magnetic interaction of Cr3+ ions in CrSe4 chains along [110]. The antiferromagnetic magnetic structure below TN is made by a spiral magnetic coupling between the ferromagnetic CrSe4 chains around crystallographic screw axes, which are parallel to an orthorhombic C axis. The spiral long‐range order of the spins of Cr3+ is incommensurate and its periodicity of q along a reciprocal lattice axis C* shows temperature dependence from about 0.47 (2.5 K) to 0.43 (18 K). The spiral periodicity of the spin order along the C axis shows a first order transition at about 21 K.