A new LaCo0.71(1)V0.29(1)O2.97(3) perovskite containing vanadium in octahedral sites: synthesis and structural and magnetic characterization

Abstract

In the course of an investigation to prepare the hypothetic new double perovskite La₃Co₂VO₉ with Co²⁺ and V⁵⁺ in octahedral sites, we obtained the new simple perovskite LaCo_0.71(1)V_0.29(1)O_2.97(3) as the main phase. The pure compound was then synthesized by the citrate decomposition method. The crystal structure was studied by X-ray (PXRD) and powder neutron diffraction (PND). Physical properties were characterized by X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and thermogravimetric analysis (TGA). Rietveld refinements were performed in the orthorhombic space group Pnma (#62). Refined cell parameters were a = 5.4762(2) Å, b = 7.7609(2) Å and c = 5.5122(1) Å. Magnetization measurements showed that this perovskite is an antiferromagnet with a Neel temperature of 15 K. At high T the magnetization follows the Curie–Weiss law corrected by temperature independent paramagnetism (TIP) showing an effective magnetic moment of 3.03μ_B well described by the contribution of Co²⁺ (HS), Co³⁺ (IS), V³⁺ and V⁴⁺ ions. The crystallographic formula was refined by PND and oxidation state distribution was determined by the combination of PND, XAS, TGA and magnetic measurements.