Study of critical behavior using the field dependence of magnetic entropy change in La0.7Sr0.3Mn1-Cu O3 (x = 0.02 and 0.04)

Abstract We report the magnetic properties and critical behavior of La 0.7 Sr 0.3 Mn 1- x Cu x O 3 ( x = 0.02 and 0.04) perovskite manganites. Results of temperature-dependent magnetization show that the Curie temperature decreases from 360 K ( x = 0.02) to 356 K ( x = 0.03) with increasing Cu content. Field dependence of isothermal entropy change data is used to estimate the critical exponents, and the results satisfied the requirements of the scaling law. Calculated critical exponents are β = 0.4641, γ = 1.1623, and δ = 3.546 for x = 0.02, and β = 0.4486, γ = 1.2024, and δ = 3.6805 for x = 0.04. These results indicate that La 0.7 Sr 0.3 Mn 1- x Cu x O 3 can be characterized by long-range mean-field behavior. Thus, the field dependence of magnetic entropy change can be effectively used in studying the critical behavior of magnetic materials.