Effect of Li doping on the magnetic and magnetocaloric properties of Pr0.5Sr0.5−xLixMnO3 (0≤x≤0.3)

The magnetic properties and magnetocaloric effect have been studied in Pr0.5Sr0.5−xLixMnO3 (0≤x≤0.3) prepared by conventional solid-state reaction. Magnetic measurements versus temperature revealed that the Curie temperature (TC) increased gradually with increasing lithium content (0.05≤x≤0.2); TC values are about 260 and 290 K for x=0.05 and 0.2, respectively. But it shows abrupt drop in TC value for x=0.3 (TC=235 K). Meanwhile, the paramagnetic–ferromagnetic (PM–FM) transition is second-order in x≤0.2, it changes into first order for x=0.3. However, the magnitude of the isothermal magnetic entropy (ΔSM) increased gradually. In a magnetic field change of 15.0 kOe, the maximum ΔSM achieved around TC are −1.03, −1.05, −1.48, −2.17 and −2.64 J kg−1 K−1 for x=0, 0.05, 0.1, 0.2and 0.3, respectively. Although ΔSM for x=0.2 is smaller compared to the composition x=0.3, the relative cooling capacity (RCP) 59.6 J kg−1 is similar compared with the value 59.8 J kg−1 for x=0.3. Addition of suitable TC makes it a desirable material for room temperature magnetic refrigeration.

► Significant magnetic entropy change induced by a low magnetic field change of 15 kOe. ► Materials undergo second-order phase transition change to first-order phase transition. ► The phase transition temperature is found around the room temperature.