Preparation, structural study from neutron diffraction data and magnetism of the disordered perovskite Ca(Cr0.5Mo0.5)O-3

摘要

We report on the preparation and characterization of the Ca(Cr0.5Mo0.5)O-3 perovskite, obtained in the search of the hypothetical double perovskite Ca2CrMoO6. This material was prepared in polycrystalline form by solid state reaction in H-2/Ar flow. It has been studied by X-ray and neutron powder diffraction (NPD) and magnetic measurements. Ca(Cr0.5Mo0.5)O-3 crystallizes in the orthorhombic Pbnm (No. 62) space group, with the unit-cell parameters a = 5.4110 (4) angstrom, b = 5.4795 (5) angstrom, c = 7.6938 (6) angstrom. There is a complete disordering of Cr3+ and Mo5+ over the B-site of the perovskite, and the (Cr,MO)O-6 octahedra are tilted by 12.4 degrees in order to optimize the Ca-O bond lengths. The magnetic susceptibility is characteristic of a ferrimagnetic behavior, with T-C = 125 K, and a small saturation magnetization at T = 5 K, of 0.05 mu(B)/f.u. (c) 2006 Elsevier Inc. All rights reserved.