Structural, microstructural and electrical properties of La 0.67(Ba,Sr)0.33MnO3 system

Abstract

La0.67(Ba,Sr)0.33MnO3 were prepared via solid-state reaction method. Rietveld refinement showed that when Ba 2+(1.49Å) is replaced with smaller ion, Sr2+(1. 32Å), its lattice parameter, volume, bond distance and angle decreases, and also different microstructure was obtained. Transition temperature, T p shifted to higher temperature while the resistance and magnetoresistance (MR) behaviour of samples were quite similar. This phenomenon believed to be due to the variation of spin-dependent scattering and/or spin-polarization tunneling across the grain surface/boundary. Typical polycrystalline (intrinsic and extrinsic MR) type of MR is shown for both samples. The highest % of low-field magnetoresistance (LFMR) (at 0.1T) of -11.5% and -10.2% at 80 K was given by La0.67Ba0.33MnO 3 (LBMO) and La0.67Sr0.33MnO3 (LSMO) samples respectively. © 2011 American Institute of Physics.