(La0.7Sr0.3MnO3)1-x/(ZrO2)x (x = 0.0–0.150, step 0.025) composites have been prepared via solid state
reaction process. The X-ray diffraction and scanning electron microscopic observations indicate that there are ZrO2 grains
separated from La0.7Sr0.3MnO3 matrix. It has been found that the inclusion of ZrO2 content decreases the conductivity,
magnetization and metal–semiconductor transition, whereas it increases the low field magnetoresistance. Possible effects of
grain boundaries on the low field magnetoresistance have been discussed. The small ZrO2 grains are trapped between
La0.7Sr0.3MnO3 grains may be acting as a barrier for spin-polarized tunneling and enhance the low-field magnetoresistance