The Structural, Magnetic, and Magnetocaloric Properties of La1-x Ag (x) MnO (3) (0.05 a parts per thousand currency sign x a parts per thousand currency sign 0.25)

Abstract

We have investigated structural, magnetic, and magnetocaloric properties of monovalent Ag-doped La1-x Ag (x) MnO3 (0.05 a parts per thousand currency sign x a parts per thousand currency sign 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 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 mu m 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 to be 82.492, 82.614, and 127.375 J/kg for x = 0.10, 0.15, and 0.25.