Two metal-insulator transitions and magnetoresistive properties investigation in La0.67Ca(0.33_x)SrxMn0.98Ni0.02O3(0.1 x 0.3)

In this paper, a study of the electrical and magnetoresistive behavior of La0.67Ca(0.33_x)SrxMn0.98Ni0.02O3(0.1 <= x <= 0.3) is shown. The temperature dependence of the electrical resistivity exhibits a metal -semiconductor transition, occurring in the temperature range between 100 and 400 K and under various magnetic fields ranging from 0 to 5 T and moving to higher temperatures under applied magnetic fields. The electrical resistivity is fitted with the phenomenological percolation model. Hence, we found that the estimated values of the resistivity are in good agreement with experimental data. Above all, the magnetoresistance study showed a peak, which has a great value around the insulator-metal transition temperature. The sample x = 0.15 is qualified by MR% = 25% which confers a giant magnetoresistance character upon this material in order to be used in the industrial fields. Concerning the other samples, they also have important MR% values of the order of 13%, 20% and 9% for x = 0.10, 0.20 and 0.30 respectively. TCRmax values are significant around room temperature.