ABSTRACT

To optimize the performance of the magnetocaloric effect in the perovskite LaMnO₃ compound, it is important to study the electronic structure, magnetic, magnetocaloric, and thermoelectric properties of this material. Using the first-principles method, the magnetic moment, the coupling interactions between magnetic atoms Mn-Mn $\left(J_{Mn-Mn}^1,J_{Mn-Mn}^2\right),$ and the crystal field are calculated. The magnetic properties of the perovskite LaMnO₃ material are determined by using the Monte Carlo simulation. It is shown that, at low temperature, the magnetization value is in good agreement with the corresponding spin at $T\sim 0.0\mathrm{K}$. In addition, the obtained Curie temperature $\left(T_C=145\mathrm{K}\right)$ is in good agreement with the experimental value. The magnetic entropy $\left(\mathrm{\Delta }{S}_{m_{max}}\right)$, the adiabatic temperature $\left(\mathrm{\Delta }{T}_a\right),$ and the relative cooling power $\left(RCP\right)$ values are $2.991\mathrm{J}/\mathrm{k}\mathrm{g}.\mathrm{K}$, $4.25\mathrm{K}$, $182.984\mathrm{J}/\mathrm{K}\mathrm{g}$, respectively. Finally, the thermoelectric properties are discussed. This material is applicable for magnetic refrigeration at Curie temperature.

摘要

为了优化钙钛矿LaMnO ₃化合物中磁热效应的性能，研究该材料的电子结构、磁、磁热和热电性能非常重要。利用第一性原理，磁矩，磁性原子Mn-Mn之间的耦合相互作用$\left(J_{米n-米n}^1,J_{米n-米n}^2\right),$并计算晶体场。钙钛矿LaMnO ₃材料的磁性能通过使用蒙特卡罗模拟确定。结果表明，在低温下，磁化值与相应的自旋在$吨～0.0\mathrm{钾}$. 此外，得到的居里温度$\left({吨}_C=145\mathrm{钾}\right)$与实验值吻合良好。磁熵$\left(\mathrm{\Delta }{秒}_{{米}_{米\mathrm{一种}X}}\right)$, 绝热温度 $\left(\mathrm{\Delta }{吨}_{\mathrm{一种}}\right),$ 和相对冷却功率 $\left(\mathrm{电阻}C磷\right)$ 值是 $2.991\mathrm{J}/\mathrm{克}\mathrm{G}.\mathrm{钾}$, $4.25\mathrm{钾}$, $182.984\mathrm{J}/\mathrm{钾}\mathrm{G}$， 分别。最后，讨论了热电特性。该材料适用于居里温度的磁制冷。