Abstract

The structural, magnetic, and magnetocaloric properties of polycrystalline (La_0.5Pr_0.5)_0.6Ba_0.4MnO₃ (LPBMO), fabricated by a conventional solid-state reaction method, are reported herein. LPBMO undergoes a second-order paramagnetic–ferromagnetic phase transition around a Curie temperature T_C ∼ 277 K. The maximum magnetic entropy change −ΔS_M^max is ∼ 3.22 J kg⁻¹ K⁻¹ for a magnetic field change of 5 T. Based on the modified Arrott plot and the iterative Kouvel–Fisher methods, a set of critical exponents (β = 0.514 ± 0.010, γ = 1.164 ± 0.013, and Δ = 3.265 ± 0.023) have been determined. These values are close to those expected for the mean-field model with long-range interactions below T_C and for the three-dimensional (3D) Ising model with short-range interactions above T_C. The effect of A-site codoping (La, Pr) on the magnetic and magnetocaloric properties of LPBMO has been analyzed and discussed.

中文翻译：

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（La 0.5 Pr 0.5）0.6 Ba 0.4 MnO 3中的磁相互作用和磁热效应：A站点共掺杂的影响

摘要

本文报道了通过常规固态反应方法制造的多晶（La _0.5 Pr _0.5）_0.6 Ba _0.4 MnO ₃（LPBMO）的结构，磁性和磁热性质。LPBMO经历周围的居里温度的第二阶顺磁性铁磁相变Ť _Ç  〜277 K.最大磁熵变-Δ小号_中号^最大值为〜3.22Ĵ千克^-1  ķ ^-1 5 T的磁场变化基于修正的阿罗特图和迭代的Kouvel-Fisher方法，一组临界指数（β  = 0.514±0.010，γ 确定了1.164±0.013和Δ = 3.265±0.023）。这些值接近于预期用于与下面远距离相互作用平均场模型Ť _Ç和用于三维（3D）伊辛与上述短距离相互作用模型Ť _Ç。分析和讨论了A位共掺杂（La，Pr）对LPBMO的磁热磁性能的影响。