Effects of Ag addition on electrical transport and magnetic properties of La0.67Ba0.33Mn0.88Cr0.12O3

Abstract We have prepared a series of polycrystalline manganites with the nominal compositions, La 0.67 Ba 0.33 Mn 0.88 Cr 0.12 O 3 /Ag x (LBMCO/Ag x ) ( x is the mole fraction) with x = 0 , 0.05, 0.1, 0.15, 0.2, 0.23, 0.27, 0.3, 0.35. The X-ray diffraction patterns show that the samples with x > 0.05 are two-phase composites. The Ag addition in LBMCO improves the properties of grain surfaces/boundaries and reduces the resistivity of the composites. For x = 0.30 sample, a minimum resistivity is obtained and a maximum room temperature magnetoresistance up to −54.5% was observed at 288 K, 1 T field. The room temperature T C and the reduced resistivity are responsible for the enhancement of room temperature MR.