Structural and magnetic properties of high-pressure/high-temperature synthesized (Sr1-xRx)CoO3 (R = Y and Ho) perovskites

摘要

Polyerystalline perovskite cobalt oxides Sr1-xRxCoO3 (R = Y and Ho; 0 <= x <= 1) were prepared by high-pressure/high-temperature technique. X-ray powder patterns of the Y-system indicated cubic perovskite form for 0 <= x <= 0.5, and orthorhombic perovskite form for x = 0.8 and 1.0, while coexisting of the two phases for x = 0.6. The cubic perovskite samples had metallic electric resistivities while the orthorhombic ones with semiconducting or insulating nature. The parent compound SrCoO3 showed a ferromagnetic transition at 266 K. With the Y substitution, the transition temperature increased slightly to similar to 275 K at x = 0.1, then decreased rapidly to similar to 60 K for x = 0.6. The YCoO3 (x = 1) sample showed non-magnetic behavior. The Ho-substituted system showed quite similar structural, transport and magnetic properties to those of the Y-system. (C) 2006 Elsevier Inc. All rights reserved.