ABSTRACT

The electronic, magnetic and magnetocaloric properties of the Iron-Selenite Bi₂₅FeO₄₀ compound have been investigated using first-principles calculations and Monte Carlo simulations (MCs). It was found that Bi₂₅FeO₄₀ is a p-type semiconductor with an indirect bandgap of about 2.16 eV which is in good agreement with the previous experimental and theoretical results. The studied compound displays a ferromagnetic behaviour with a spin moment of the unit cell of about 4.06 μ_B. The Bi₂₅FeO₄₀ compound exhibits a weak ferromagnetic behaviour around T_C = 271.96 K; this value is in good agreement with experimental results. In addition, it shows a magnetocaloric effect (MCE) around the Curie temperature (T_C), with the maximum values of the magnetic entropy change $\left(\mathrm{\Delta }{S}_m^{\mathrm{M}\mathrm{a}\mathrm{x}}\right)$ and relative cooling power (RCP) are 2.56 J.kg⁻¹.K⁻¹and 55.01 J/Kg, respectively, under applied an external magnetic field of h = 5.00 T. The good magnetocaloric properties reveal the applicability of Bi₂₅FeO₄₀ compound to the magnetic refrigeration around T_C.

摘要

已经使用第一性原理计算和蒙特卡罗模拟 (MC)研究了铁-亚硒酸盐 Bi ₂₅ FeO ₄₀化合物的电子、磁性和磁热特性。发现Bi ₂₅ FeO ₄₀是具有约2.16 eV的间接带隙的p型半导体，这与先前的实验和理论结果非常一致。所研究的化合物表现出铁磁行为，晶胞的自旋矩约为 4.06 μ _B。Bi ₂₅ FeO ₄₀化合物在T _C附近表现出弱铁磁行为 = 271.96 K；该值与实验结果非常吻合。此外，它显示了居里温度附近（一磁热效应（MCE）Ť _Ç），用磁熵变的最大值$\left(\mathrm{\Delta }{秒}_{米}^{\mathrm{米}\mathrm{一种}\mathrm{X}}\right)$在施加h  = 5.00 T的外部磁场下，相对冷却功率 (RCP) 分别为 2.56 J.kg ^-1 .K ^-1和 55.01 J/Kg 。良好的磁热性能表明 Bi ₂₅ FeO ₄₀的适用性复合到T _C周围的磁制冷。