Phase transitions and electrical transport in the mixed-valence V2+/V3+ oxide BaV10O15

BaV10O15 can be regarded as a Ba-doped V2O3 in which the Ba2+ ions substitute in the O2− close-packed layers. The Ba2+ ions order within these layers and direct the occupation of the octahedral sites by V2+ and V3+ ions resulting in a structure with subtle differences from that of V2O3 which can be described in Cmca at room temperature. Magnetic susceptibility data show evidence for two phase transitions at 135 and 40K. The higher temperature …