Enhanced low field magnetoresistance in La0.7Sr0.3MnO3-La2O3 composites

► Polycrystalline composites between La0.7Sr0.3MnO3 (LSMO) and La2O3 phases. ► The maximum LFMR value of 2.22% at 300 K in 500 Oe from the composite sample with 10 mol% La2O3 addition. ► Low resistivity level (<1 Ω cm) far below the metallic percolation threshold. ► Closely related with a characteristic microstructure variation of composite samples. ► High grain boundary areal density and sharpening of a disordered LSMO grain boundary region acting as more effective spin-dependent scattering centers.