Structural, magnetic and magnetocaloric properties of Ag-doped Pr0.5Sr0.5-xAgxMnO3 manganites (0.0≤x≤0.4)

Abstract

The effects of partial silver substitution on the structural, magnetic and magnetocaloric properties of Pr0.5Sr0.5-xAgxMnO3 (0.0≤x≤ 0.4) compounds have been studied. Our powder specimens are synthesized using the sol-gel method at high temperatures. X-Ray diffraction study reveals that all compounds crystallize in the distorted orthorhombic symmetry with Pbnm space group. Magnetization measurements versus temperature under 0.05T reveal the presence of an antiferromagnetic (AFM) to ferromagnetic (FM) transition at low temperatures for the parent compound, followed by a second one from FM to paramagnetic state (PM). Ag doping is found to reinforce the FM behavior with a Curie temperature (TC) increasing from 268 (x=0.0) to 305K(x=0.2). However, for higher Ag amount, TC decreases again from 285K (x=0.3) to 170K (x=0.4). The maximum of the magnetic entropy change (-ΔSMmax) was calculated using the isothermal magnetization curves M (H) under magnetic field change of 5T and is found to be 4.7J/(kg K) for x=0.3. The relative cooling power (RCP) turns out to be 188J/kg and 229J/kg for x=0.0 and x=0.1, respectively. This suggests that these compounds may be suitable candidates for magnetic refrigeration.