Structural and Magnetic Characterization of NdCaCrO4 Oxide

• Published in: Journal of solid state chemistry 1999-12, Vol.148 (2), p.361-369
• Main Authors: Romero de Paz, J., Hernández Velasco, J., Fernández-Díaz, M.T., Porcher, P., Martínez, J.L., Sáez Puche, R.
• Format: Article
• Language: English
• Subjects: antiferromagnetic order; 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; Inorganic compounds; Magnetic properties and materials; magnetic structure; NdCaCrO4 oxide; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); spin reorientation; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Water, oxides, hydroxides, peroxides
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1999.8461

The structural and magnetic properties of NdCaCrO4 oxide have been studied mainly by means of neutron powder diffraction. This oxide presents orthorhombic symmetry, space group Bmab, with lattice parameters at room temperature a=5.3739(1) Å, b=5.54114(1) Å, and c=11.9536(3) Å. At around 973 K a reversible phase transition to a tetragonal (I4/mmm) structure has been determined from X-ray powder diffraction data. Below 180 K, NdCaCrO4 shows antiferromagnetic ordering in the Cr3+ sublattice that has been explained on the basis of a propagation vector k=0 and a collinear magnetic structure, with a symmetry mode Gx. At 30 K an antiferromagnetic ordered component along the z direction appears. This spin reorientation could be induced by the onset of local magnetic interactions between the neodymium and chromium sublattices.