The Structural, Magnetic, and Magnetocaloric Properties of La1−x Ag x MnO 3 (0.05 ≤ x ≤ 0.25)

Abstract

We have investigated structural, magnetic, and magnetocaloric properties of monovalent Ag-doped La 1−x Ag x MnO 3 (0.05 ≤ x ≤ 0.25) compounds. The materials were prepared by the sol-gel method and then characterized by X-ray diffraction (XRD). The XRD results indicated that all the samples have a single phase of hexagonal (rhombohedral) structure with the R3c space group. The morphology and particle size distributions were investigated using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The SEM images showed that the grain sizes are smaller than 1 μm and remain the same with increasing Ag concentrations. The magnetic properties were studied by measuring magnetization and varying temperature (M(T )) and external magnetic field (M(H )). The M(T ) measurements show that with decreasing temperature all samples exhibit a paramagnetic-to-ferromagnetic phase transition. The Curie temperature, T C , increases from 200 to 290 K as Ag doping increases from 0.05 to 0.25. The magnetic entropy change (|−SM|) is obtained in all samples near the Curie temperatures at a magnetic field change of 3 T. Furthermore, their maximum relative cooling power (RCP) values were found A. Coşkun to be 82.492, 82.614, and 127.375 J/kg for x = 0.10, 0.15, and 0.25.

Research Progress of Doped Manganite Materials in Magnetic Refrigeration

“…The principle of DE is shown in Figure 1. To better adjust the MCE and temperature of the magnetic phase transition, scientists have focused primarily on doping rare earth elements or AE to replace the A and B sites of perovskite manganite (CosKun et al, 2016;Ghosh and Ghatak, 2016;Sfifir et al, 2017).…”