Exploring the mixed valency of chromium in calcium-doped DyCrO3: Structural and magnetic properties

Abstract

A series of new mixed rare-earth orthochromite solid solutions, Ca_xDy_1-xCrO₃ (x = 0.0, 0.1, 0.2, 0.3, 0.4), are synthesized using the solid-state route at 1100 °C. The distorted orthorhombic phase is retained till 40 mol% of Ca substitution in the series of solid solutions forming an A-site disordered orthorhombic perovskite. The structural characterizations of the solid solution show that the larger-sized and divalent Ca induces structural changes. The orthorhombic lattice is compressed by approximately 0.47 %, and the octahedral distortion has increased severalfold despite decreased octahedral tilting angles and increased average A-site cation size. The charge neutrality is maintained by promoting tri-valent Cr to tetravalency, compensating for the increase in mean Dy-site radius with larger-sized Ca substitution and decreasing the net magnetization in the series of solid solutions verified by XPS. The antiferromagnetic nature is retained in the whole series of compounds, whereas the ferromagnetic contribution to the overall magnetic moment decreases with decreased Dy content.