Effect of sintering temperature on electrical transport in La0.67 Ca0.33 MnO3/BaTiO3composites

It is shown that the electrical transport in ferromagnet-ferroelectric-type La0.67Ca0.33MnO3/BaTiO3 composites fabricated by the sol-gel method strongly depends on sintering temperature (Ts). For the Ts > 1000 0C samples, the insulator-metal transition temperature (TIM) decreases with increasing BaTiO3 content and the magnetoresistance (MR) is enhanced at low temperature (T < TIM). For the Ts = 1000 0C samples, the TIM value initially increases with an increase of BaTiO3 content and thereafter it decreases as BaTiO3 content further increases. For the Ts = 900 0C samples, the TIM value increases throughout the increase in BaTiO3 content and MR is enhanced over the whole temperature range studied. The experimental results have been discussed in terms of the magnetoelectric coupling effect and the interfacial diffusion reaction, especially at grain boundaries