Study of structural effect on Eu-substituted LSMO manganite for high temperature coefficient of resistance

In this work, Eu substituted La_0.7Sr_0.3MnO₃ (LSMO) is studied to achieve high temperature coefficient of resistance (TCR). The compounds La_0.7−xEu_xSr_0.3MnO₃ with x=0, 0.1 0.2 and 0.3 are prepared by solid state reaction route and their structural and transport properties are examined by different characterization techniques. The metal–semiconductor/insulator transition temperature (T_MI) decreases from 390 K (for x=0) to 240 K (for x=0.3) with decrease in average ionic radius 〈r_A〉 of A-site. The maximum TCR percentage of La_0.7−xEu_xSr_0.3MnO₃ compound is found to be increased for x=0.2 (1.9%) and for x=0.3 (3.36%) compared to its parent compound La_0.7Sr_0.3MnO₃ (1.1%). The substitution of Eu increases the lattice distortion, which enhances the TCR value from 1.1% to 3.36%. The robustness of distortion increases with decreasing 〈r_A〉 which is well correlated with the high magneto-resistance, and high TCR findings