Effect of V addition on magnetic, transport, and microstructural properties of La0.7Sr0.3MnO3

The microstructural, magnetic, and magnetotransport properties of polycrystalline samples with nominal composition of La0.7Sr0.3Mn1-xVxO3 (0≤x≤0.25) sintered in air have been investigated. It is found that V could not substitute for Mn to form La0.7Sr0.3Mn1-xVxO3. The samples contain several phases such as (La,Sr)Mn1-δO3, LaSr3V3O12, Mn3O4 etc. and constitute multi-phase composites. The Sr-V-rich phase form a liquid phase during sintering process and the sintering be long to liquid-phase sintering, which may effectively promote grain growth of (La,Sr)Mn1-δO3 phase. The Curie temperature TC and saturation magnetization of the composites decrease with increasing the V content x. The addition of V may effectively improve the low-field MR response at low temperatures due to the variation in the microstructure of the composites. The MR ratio at a low field of 2 kOe reaches 25% for the x=0.15 sample at 84 K. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)