Physical properties of La_0.7Ca_0.2Sr_0.1MnO₃ manganite: a comparison between sol–gel and solid state process

We have synthesized La_0.7Ca_0.2Sr_0.1MnO₃ sample using two different methods: the solid-state reaction (S1) and the sol–gel process (S2). Structural, morphological, infrared and magnetic properties were investigated by X-ray diffraction, scanning electron microscopy, Spectrum Two FT-IR Spectrometer and vibrating sample magnetometer. Despite the various conditions employed in the elaboration, the crystallographic study shows that our samples are single phase and crystallize in orthorhombic system with Pnma space group. A small difference appears in the microstructural and magnetic properties. The Curie temperature T_C is found to be 308–256 K for S1 and S2 respectively. A large magnetocaloric effect has been observed in both samples, besides; the relative cooling power for S2 is bigger than S1. It attains exactly 250.75 J kg⁻¹ under a magnetic applied field of 5 T. These results show that the elaboration process has an important impact on the magnetic and magnetocaloric properties. Furthermore, the importance of the magnetoelastic coupling and electron interaction in the magnetocaloric properties of manganite was confirmed by the analysis of Landau theory.