Effects of electron injection on the magnetic and magnetocaloric behavior of Sr2FeMoO6 double perovskite

With the aim of determining and distinguishing the influence of rare-earth doping on the strength of magnetic interactions, magnetic and magnetocaloric properties of Sr2-xPrxFeMoO6 (x = 0.0, 0.1, 0.2, 0.3) double perovskite were investigated. The X-ray diffraction analysis revealed that all the samples crystallized in a tetragonal structure with 14/mmm space group. The temperature dependent magnetization and Arrott analysis suggested a second order of ferromagnetic phase transition in all the synthesized samples. The competing interaction between the electron injection and steric effect resulted in a non monotonic evolution of the Curie temperature (Tc). In the low Pr doped samples the raising of the Curie temperature is mainly due to the electronic effects while the decrease in Tc observed for higher Pr doping (x = 0.3) is attributed to the steric effects. The magnetization was observed to increase with the increasing Pr doping (up to x = 0.2) indicating a progressive increase in cationic ordering. The magnetic entropy change was evaluated from the measurement of isothermal magnetization with respect to the magnetic field at different temperatures. The maximum magnetic entropy change and the relative cooling power were found to increase with the increasing Pr doping (x <= 0.2). The tunability of magnetization as well as Curie temperature simply by adjusting the dopant concentration and synthesis conditions makes Sr2FeMoO6 a potential candidate for exploring the new kind of magnetic refrigerants. (C) 2016 Elsevier B.V. All rights reserved.