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 TN=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 TN probably reflect a covalent-mixing parameter λ near the critical value λc for localized vs collective electron behavior.