Effects of ferrites on magnetic transport properties in La2/3Sr1/3MnO3/ferrites composites

Effects of soft-magnetic MnZn ferrite (Mn0.3Zn0.5Fe2O4, MZF) and hard-magnetic Ba ferrite (BaO.6Fe2O3, BaM) on the structure and magnetic transport properties of [La2/3Sr1/3MnO3] (LSMO)/(x) [ferrites] (ferrites=MZF, BaM) composites have been investigated. It was found that the inclusion of MZF phase reduces magnetization and ferromagnetic-paramagnetic transition temperature (Tc) of the composites. With increasing the content of the dopants, the high-temperature magnetoresistance (MR) decreases, whereas low-temperature MR increases and reaches 42% at 150 K and x=0.1. However, for the LSMO/BaM composites, magnetization and ferromagnetic-paramagnetic transition temperature (Tc) decrease firstly as x<5%, and then increase as x>5%. The resistivity of the composites increases by five orders of magnitude at x=1% and is out of measured range at x=5%. High magnetic field has little effect on the resistivity and magnetoresistance for the composites with x>5%, which may originate from the pinning effect of BaM grains.