Low-field magnetoresistance of (1 − x)La0.7Ca0.3MnO3 + xAg composites

摘要: Abstract Low-field magnetoresistance of (1 −  x ) La 0.7 Ca 0.3 MnO 3  +  Ag (LCMO/Ag) composites have been reported in this paper. The low-field ( LFMR ), the conductivity σ and metal–insulator transition temperature T p increases when increasing content Ag. In order to explore basic physics behind dependence MR , we analyzed our data light a phenomenological model, which was based on spin-polarized transport conduction electrons at grain boundaries. We find that is described by an expression as Curie–Weiss law-like behavior, i.e., ) =  b /( c ). Finally, attributed feature surface magnetization nanosize granular LCMO/Ag samples, role becomes very much dominant for nanodimensional manganite composites.