Influence of La addition on the structural, magnetic and magnetocaloric properties in Sr 2−x La x FeMoO 6 (0≤ x ≤0.3) double perovskite

Abstract We report the effect of carrier doping via partial substitution of La 3+ for Sr 2+ on the structural, magnetic and magnetocaloric properties of Sr 2 FeMoO 6 double perovskite. Polycrystalline Sr 2− x La x FeMoO 6 ( x =0.0, 0.1, 0.2, 0.3) samples were prepared using the conventional solid state reaction method. Using the X-ray diffraction (XRD) analysis it was established that all the samples crystallized in a tetragonal structure with I 4/ mmm space group. An increase in the La doping lead to an increase in the lattice parameter ‘ a’ and the volume of the unit cell. The lattice parameter ‘ c’ however remained unchanged. The temperature variation in magnetization and Arrott analysis suggested a second order of ferromagnetic phase transition in all samples with Curie temperature, T C increasing from 358 K for x =0.0–365 K for x =0.3. A gradual increase in magnetization was also observed with the increasing La content up to x =0.2. The magnetic entropy change was calculated from the measurement of isothermal magnetization versus magnetic field at different temperatures. The tunability of magnetization and T C simply by adjusting the concentration of La and synthesis conditions makes Sr 2 FeMoO 6 an attractive material for magnetic refrigeration at desired temperature.