The physical mechanism of magnetic field controlled magnetocaloric effect and magnetoresistance in bulk PrGa compound.
The physical mechanism of magnetic field controlled magnetocaloric effect and magnetoresistance in bulk PrGa compound.
复制标题
块状 PrGa 化合物中磁场控制磁热效应和磁阻的物理机制
DOI：
10.1038/srep14970
复制
发表时间：
2015-10-12
影响因子：
4.6
通讯作者：
Shen BG
中科院分区：
文献类型：
--
作者：
Zheng XQ;Wu H;Chen J;Zhang B;Li YQ;Hu FX;Sun JR;Huang QZ;Shen BG
PrGa化合物在磁热效应（MCE）和磁电阻（MR）方面表现出优异的性能。在磁性测量、热容测量和中子粉末衍射（NPD）实验的基础上，对PrGa化合物中MCE和MR的物理机制进行了详细的研究和阐述。NPD沿着饱和磁矩（MS）和磁熵（SM）的计算结果表明，在铁磁（FM）温度范围内，磁矩在等效锥面内是随机分布的。PrGa化合物随着温度升高经历FM到FM转变和FM到顺磁（PM）转变。详细讨论了磁化过程，并研究了磁致热效应和磁电阻效应的物理机制。从磁结构和磁化过程的分析出发，解释了MCE曲线平台的形成，并详细计算了MR。实验结果与计算结果吻合得很好。最后讨论了MR = β（T）X2的表达式及其应用条件，其中X为M（H）/Meff，Meff为顺磁有效磁矩。
The PrGa compound shows excellent performance on the magnetocaloric effect (MCE) and magnetoresistance (MR). The physical mechanism of MCE and MR in PrGa compound was investigated and elaborated in detail on the basis of magnetic measurement, heat capacity measurement and neutron powder diffraction (NPD) experiment. New types of magnetic structure and magnetic transition are found. The results of the NPD along with the saturation magnetic moment (MS) and magnetic entropy (SM) indicate that the magnetic moments are randomly distributed within the equivalent conical surface in the ferromagnetic (FM) temperature range. PrGa compound undergoes an FM to FM transition and an FM to paramagnetic (PM) transition as temperature increases. The magnetizing process was discussed in detail and the physical mechanism of the magnetic field controlled magnetocaloric effect (MCE) and the magnetoresistance (MR) was studied. The formation of the plateau on MCE curve was explained and MR was calculated in detail on the basis of the magnetic structure and the analysis of the magnetizing process. The experimental results are in excellent agreement with the calculations. Finally, the expression of MR = β(T)X2and its application conditions were discussed, where X isM(H)/Meffand Meffis the paramagnetic effective moment.