Study on the Critical Behavior and Magnetocaloric Effect of La0.7−xEuxBa0.15Ca0.15MnO3 (0 ≤ x ≤ 0.08)

The structure, magnetic properties, critical behavior, and magnetocaloric effect (MCE) of La0.7−xEuxBa0.15Ca0.15MnO3 (x = 0, 0.02, 0.04, 0.06, and 0.08) samples have been investigated in the paper. The samples have a rhombohedral crystal structure with the R-3C space group. The magnetic entropy change (− ∆SM) of the samples increases from 2.8 to 3.43 J/kg K (μ0H = 5 T) with increasing Eu3+ content. The Curie temperature (TC) decreases from 228 to 187 K; however, the relative cooling power (RCP) increases from 308 to 340 J/kg due to the weakness of the double-exchange interaction with the Eu3+ content. The samples undergo the second-order magnetic phase transitions with the critical parameters of TC = 191 K, β = 0.849, γ = 1.078, and δ = 2.242. The exponents are close to the mean-field values, which means large disorder of spin magnetic moments in the sample. Our work provides a method to tailor the working temperature of MCE in magnetic refrigeration while maintaining or even increasing the magnetic entropy change.