Structural, magnetic and transport properties of La0.70Sr0.21K0.09MnO3

In this work we investigated structural, magnetic and transport properties of La0.70Sr0.21K0.09MnO3 compound produced by the standard sol-gel route. The crystal structure was determined by analyzing XRD data and found to be an orthorhombic perovskite belonging to Pnma space group. The Curie temperature, T-C, of the compound was determined to be 295 K, which is near room temperature. The calculated magnetic entropy change was 0.77 J/kg K which is not high enough for magnetic cooling application. Insulator-Metal transition temperature, T-IM, was determined to be 294 K, which coincides with T-C. The low temperature peak near T-IM reveals the coexistence of ferromagnetic and paramagnetic phases in the ferromagnetic region. The temperature dependence of resistivity was well fitted (with R-2 = 0.9999) to rho(T) = rho(0) + rho T-0.5(0.5) + rho T-2(2) + rho T-4.5(4.5) in a wide temperature interval including low temperature resistivity upturn. (C) 2013 Elsevier B. V. All rights reserved.