Understanding the large rotating magnetocaloric effect in TbMn1-xFexO3single crystals upon q-Fermi Dirac nonextensive statistics
Understanding the large rotating magnetocaloric effect in TbMn1-xFexO3single crystals upon q-Fermi Dirac nonextensive statistics
复制标题
基于 q-费米狄拉克非广延统计了解 TbMn1-xFexO3 单晶中的大旋转磁热效应
DOI：
10.1016/j.jallcom.2017.09.049
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发表时间：
2017
影响因子：
6.2
通讯作者：
Zhang Jincang
中科院分区：
文献类型：
--
作者：
Fang Yifei;Qiang Gang;Liu Xinzhi;Chen Fei;Zhang Jincang
在磁性材料中，在其磁相变温度附近具有大的磁晶各向异性的那些材料中预期大的磁热效应。本文报道了TbMn 1-xFexO 3（x= 0，0.75）单晶在2 ~ 50 K温度范围内，在c平面内恒定外场旋转时的旋转磁热效应的比较研究。在TbMnO 3和TbMn0.25Fe0.75O3中观察到a轴和c轴之间的磁熵变，并具有很强的磁晶各向异性. TbMn 0.2 5 Fe 0.75 O3在16 K时表现出的大磁热效应接近于自旋重取向，从TbMn 0.2 5 Fe 0.75 O3的自旋重取向为TbMn 0.2 5 Fe 0.75 O3的自旋重取向为TbMn 0.2 5 Fe 0.75 O3的自旋重取向。TbMnO 3（TbMn0.25Fe0.75O3）在7 T下的最大磁熵变和制冷量分别达到19.20J/Kg K（14.84J/Kg K）和411.97J/Kg（260.80J/Kg）。此外，利用Lorentz透射电子显微镜技术，我们发现TbMn0.25Fe0.75O3材料具有大的单畴结构，尺寸可达3 μm× 3 μm，表明该系统具有大的磁晶各向异性.基于非广延热力学，我们进一步采用q-Fermi Dirac统计来证明磁化强度随旋转角度的计算结果与实验结果之间的良好一致性。结果表明，TbMn 1-xFexO 3体系的磁性能和磁热性能的差异主要是由磁晶各向异性能的大小决定的.
In magnetic materials, a large magnetocaloric effect is expected in those with large magnetocrystalline anisotropy in the vicinity of their magnetic phase transition temperature. Here we report a comparative study of rotating magnetocaloric effect in TbMn 1-x Fe x O 3 (x= 0, 0.75) single crystals by rotating them in a constant external field within a c plane from 2 to 50 K. We observed a large magnetic entropy change between a and c axes with strong magnetocrystalline anisotropy in TbMnO 3 as well as TbMn 0.25 Fe 0.75 O 3. For TbMn 0.25 Fe 0.75 O 3, the large magnetocaloric effect appears close to a spin reorientation from Γ 1 (A x, G y, C z) to Γ 4 (G x, A y, F z) magnetic configuration at∼ 16 K, which is distinguished from that of TbMnO 3 near the antiferromagnetic ordering of Tb 3+ ions at∼ 9 K. The maximum of magnetic entropy change and refrigerant capacity of TbMnO 3 (TbMn 0.25 Fe 0.75 O 3) reach as high as 19.20 J/Kg K (14.84 J/Kg K), 411.97 J/Kg (260.80 J/Kg) under 7 T, respectively. Furthermore, using Lorentz transmission electron microscopy technique, we show the TbMn 0.25 Fe 0.75 O 3 material displays a large single domain structure with dimension up to about 3 μm× 3 μm, as an indicative of a large magnetocrystalline anisotropy in this system. Based on nonextensive thermodynamics, we further employ the q-Fermi Dirac statistics to demonstrate the good consistency between computed and experimental results of magnetization versus rotating angles. Our results clearly indicate the magnetocrystalline anisotropy energy plays a decisive role in the large differences of the magnetic properties and magnetocaloric properties in TbMn 1-x Fe x O 3 system.