Vanadium-doping effects on magnetic and magnetocaloric efficiency of La0.7Sr0.2(CaLi)0.05Mn1−xVxO3 [x = 0.00 and x = 0.05] manganites.

The La_0.7Sr_0.2Ca_0.05Li_0.05Mn_1−xV_xO₃ [S₁(x = 0) and S₂(x = 0.05)] polycrystalline compounds are found to exhibit a ferromagnetic—paramagnetic transition (FM-PM) when temperature increases with a decrease of Curie temperature T_C when substituting Mn with V from T_C = 271 K to T_C = 266 K. The Arrott plots near Curie temperature show positive slopes under an applied magnetic field varying from 0 to 5 T showing a second order magnetic transition for our samples. Basing on the magnetic-field dependences of magnetization measured around T_C, maximum magnetic-entropy changes ΔSMmax,<inline-graphic></inline-graphic> under the applied field of 5 T, are about 5.4 and 4.8 J kg⁻¹ K⁻¹ for S₁ and S₂ respectively. The efficiency of our samples for magnetic refrigeration application has been evaluated throw calculating the relative cooling power (RCP) values, which were equal to 211.5 J kg⁻¹ for S₁ and 195.5 J kg⁻¹ for S₂. The study of the universal curves show that the rescaled magnetic entropy change curves for different applied fields collapse onto a same curve confirming that both S₁ and S₂ reveal a second order transition. [ABSTRACT FROM AUTHOR]