Tb掺杂双钙钛矿氧化物Pr2CoMnO6的磁热效应

采用高温固相反应法制备双钙钛矿氧化物Pr_(2-x)Tb_xCoMnO₆(x=0,0.05,0.1,0.15)系列陶瓷样品，研究了Tb的掺杂量对Pr₂CoMnO₆样品的居里温度、磁熵变以及磁相变的影响。结果表明:系列样品Pr_(2-x)Tb_xCoMnO₆(x=0,0.05,0.1,0.15)的空间点群为单斜晶系P2₁/n，具有良好的单相性;该组样品均有两个磁转变点(T_C1和T_C2)；随着Tb掺杂量的增加T_C1和T_C2均降低下降；在测量温区内，随着温度的降低4个样品均先后经历顺磁态、顺磁-铁磁共存态；该组样品在7 T外加磁场中的最大磁熵变值ΔS_M分别为-1.862、-1.779、-1.768和-1.766 J/(kg·K)。掺杂Tb元素使最大磁熵变值变小，但是拓宽了半高宽温区。结合RCP值可以判断，Pr_1.9Tb_0.1CoMnO₆比其他三个样品更具有作为高温区磁制冷材料的潜能；根据对Arrott曲线、重标定曲线以及Loop曲线的分析，该组样品在此阶段经历了一级相变。

Magnetocaloric Effect of Tb-doped Double Perovskite Oxide Pr2CoMnO6

A series of double perovskite oxide Pr_(2-x)Tb_xCoMnO₆ (x=0, 0.05, 0.1, 0.15) was prepared by high temperature solid state reaction. The effect of Tb-doping on the Curie temperature, magnetic entropy change and magnetic phase transition of double perovskite oxide Pr₂CoMnO₆ was investigated by analyzing the relevant data. The results show that the series of double perovskite oxides Pr_(2-x)Tb_xCoMnO₆ (x=0,0.05,0.1,0.15) all is good single-phase with crystallographic structure of monoclinic P2₁/n; they all have two magnetic transition points (T_C1 and T_C2); T_C1 and T_C2 decrease with the increasing Tb-content; within the desired temperature region, as the temperature decreases the state of the prepared four double perovskite oxides underwent the following transition: paramagnetic state, paramagnetic-ferromagnetic and coexistence state; by a given external magnetic field of 7 T, the maximum magnetic entropy change ΔS_{Mof the prepared four double perovskite oxides is -1.862, -1.779, -1.768 and -1.766 J/(kg·K) respectively. In other word, Tb-doping makes the maximum magnetic entropy change smaller, but increases its half-height wide temperature range. It can be judged that among others, Pr1.9Tb0.1CoMnO6 is the most potential candidate as a high-temperature magnetic refrigeration material especially, regarding to its RCP value; Based on the analysis of the Arrott curve, the recalibration curve and the Loop curve, the four double perovskite oxides underwent a first-order phase transition during the process.}