Magnetocaloric effect and critical properties in La_0.85Li_0.15MnO₃

The manganite La_0.85Li_0.15MnO₃ (LLMO) was synthesized by standard ceramic preparation routes, its magnetocaloric effect and critical phenomenon have been studied by measurements of dc-magnetization. The sample is of single phase with a rhombohedral structure confirmed by the X-ray diffraction refinement. M–T data reveal that the LLMO shows a second-order magnetic transition with a T_C of 235 K. Maximum values of magnetic entropy change (− ∆S_M^max= 5.32 J K⁻¹ Kg⁻¹) and relative cooling power (RCP = 320.3 J kg⁻¹) have been observed when the magnetic field change is up to 5 T. The LLMO compound with excellent magnetocaloric effect is expected to have effective applications in sub-room temperature range. In addition, the critical behavior around its T_C is thoroughly analyzed using the field dependence of the magnetic entropy change. The determined values of critical exponents (β = 0.507, γ = 1.045, and δ = 2.982) are fairly close to the theoretical values of the mean field model (β = 0.5, γ = 1.0, and δ = 3.0), indicating the presence of long-range ferromagnetic ordering in this system. The validity of the obtained exponents is confirmed by the scaling theory.