ABSTRACT

In our present work, La_0.75Ca_0.25–xNa_xMnO₃ (0 ≤ x ≤ 0.10) samples were synthesized by the flux method. The structural and the magnetocaloric properties were studied. The crystallographic study indicates that our samples crystallize in the orthorhombic structure, with Pbnm space group. The magnetocaloric properties have been theoretically studied and compared with the experimental results, under low magnetic field of 0.05 T. It has been found that the simulated data M(T), −ΔS_M (T), ΔT_ad and ΔC_P,H (T) are in good agreement with the experimental one. In addition, the magnetocaloric effect of Na⁺ in our system is important and beneficial for manipulating magnetocaloric refrigeration.

摘要

在我们目前的工作中，La _0.75 Ca _{0.25– x} Na _x MnO ₃ (0 ≤  x  ≤ 0.10) 样品是通过助熔剂法合成的。研究了结构和磁热特性。晶体学研究表明我们的样品以正交结构结晶，具有 Pbnm 空间群。在0.05 T的低磁场下，对磁热特性进行了理论研究并与实验结果进行了比较，发现模拟数据M(T)、-Δ S _M ( T )、Δ T _ad和Δ C _{P ,H} ( T) 与实验一致。此外，我们系统中 Na ⁺的磁热效应对于操纵磁热制冷很重要且有益。