Preparation, structural study from neutron diffraction data and magnetism of the disordered perovskite Ca(Cr0.5Mo0.5)O3

We report on the preparation and characterization of the Ca(Cr0.5Mo0.5)O3 perovskite, obtained in the search of the hypothetical double perovskite Ca2CrMoO6. This material was prepared in polycrystalline form by solid state reaction in H2/Ar flow. It has been studied by X-ray and neutron powder diffraction (NPD) and magnetic measurements. Ca(Cr0.5Mo0.5)O3 crystallizes in the orthorhombic Pbnm (No. 62) space group, with the unit-cell parameters a=5.4110 (4) Å, b=5.4795 (5) Å, c=7.6938 (6) Å. There is a complete disordering of Cr3+ and Mo5+ over the B-site of the perovskite, and the (Cr,Mo)O6 octahedra are tilted by 12.4° in order to optimize the Ca–O bond lengths. The magnetic susceptibility is characteristic of a ferrimagnetic behavior, with TC=125 K, and a small saturation magnetization at T=5 K, of 0.05 μB/f.u.