A comparative study of La0.65Ca0.2(Na0.5K0.5)0.15MnO3 compound synthesized by solid-state and sol-gel process

Abstract In this paper, we investigated the impact of the elaborating method on the structural, magnetic and magnetocaloric properties of La 0.65 Ca 0.2 (Na 0.5 K 0.5 ) 0.15 MnO 3 powder sample, synthesized by both methods: solid state (SS) and sol gel (SG) process. The two compounds were firstly analyzed by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) to determine the temperature transformation into the perovskite structure. The Rietveld refinement of the X-ray powder diffraction show that both samples are single phase and crystallize in the orthorhombic structure with Pbnm space group. The surface morphology of the samples was carried out using scanning electron microscopy (SEM). Magnetization measurements versus temperature in a magnetic applied field of 0.05 T indicate that both samples exhibit a paramagnetic-ferromagnetic transition with decreasing temperature. Curie temperature T C is found to be 296 and 260 K for SS and SG samples, respectively. The maximum of the magnetic entropy change, | Δ S M M a x | , is lower in the SG sample than in the SS sample, but the thermal variation of − ΔS M is broader, resulting in a higher relative cooling power (RCP).