Magnetic and magnetocaloric effect study of a polycrystalline Gd 0.5 Sr 0.5- x Ca x MnO 3 compound.

The magnetic and magnetocaloric properties of polycrystalline Gd _0.5 Sr _{0.5- x} Ca _x MnO ₃ ( x = 0.0, 0.2, 0.3, 0.4 and 0.5) compounds have been investigated. Depending upon the Ca and Sr proportions, fascinating magnetic ground states were observed in the Gd _0.5 Sr _{0.5- x} Ca _x MnO ₃ compounds. Here, the dominating nature of the canted magnetic state (for the Gd _0.5 Ca _0.5 MnO ₃ compound) and glassy (disordered ferromagnetic) magnetic state (for the Gd _0.5 Sr _0.5 MnO ₃ compound) are observed. However, for the intermediate doped samples ( x = 0.2, 0.3, 0.4), a competing nature is found in their magnetic and exchange bias properties. Additionally, in the low temperature region, a significantly large magnetocaloric effect is observed for all the samples. At a 70 kOe external magnetic field, the highest observed value of the magnetocaloric entropy change is 21.58 J kg ^-1 K ^-1 (for the Gd _0.5 Ca _0.5 MnO ₃ sample) and the lowest is 10.15 J kg ^-1 K ^-1 (for the Gd _0.5 Sr _0.5 MnO ₃ sample).