Single-Crystal Growth and Properties of the Perovskites LaVO3 and YVO3

Abstract

LaVO₃ and YVO₃ are intermediate between LaTiO₃ (metallic and Pauli paramagnetic) and LaCrO₃ (an insulator and antiferromagnetic below T_N=320°K). Single crystals of these vanadites were grown from the melt by a modified Bridgman technique. The temperature dependences of electrical resistivity indicate that both materials are semiconductors in the temperature range 120°–670°K. However, the activation energies for semiconduction are considerably lower than those reported in the literature for powder specimens. Magnetic susceptibilities reveal antiferromagnetic ordering at 137° and 110°K for LaVO₃ and YVO₃, respectively. LaVO₃ undergoes a structural transition at the Néel point that is suggestive of spin‐orbit‐coupling electron ordering. These results clearly support a localized‐electron model at low temperatures. However, the low activation energies for semiconduction at temperatures above T_N probably reflect a covalent‐mixing parameter λ near the critical value λ_c for localized vs collective electron behavior.