Low-field magnetoresistance in La_(0.7)Sr_(0.3)MnO_3/BaTiO_3 composites

摘要

A manganite composite series of (1 - x) La_(0.7)Sr_(0.3)MnO_3/xBaTiO_3 (x = 0, 0.06, 0.12, and 0.18) has been fabricated by solid-state reaction combined with a high-energy mechanical milling method. Experimental results revealed that the insulator-metal transition temperature was shifted towards lower temperatures, and resistivity increases with increasing BaTiO_3 content in (1 - x)La_(0.7)Sr_(0.3)MnO_3/xBaTiO_3. Meanwhile, the ferromagnetic-paramagnetic transition temperature was almost unchanged. The increase in magnetoresistance was observed in the all composites at whole measurement temperatures under an applied magnetic field of 3 kOe. Here, temperature dependences of magnetoresistance display a Curie-Weiss law-like behavior. The nature of this phenomenon is explained in detail.