Dimension reduction induced anisotropic magnetic thermal conductivity in hematite nanowires
Dimension reduction induced anisotropic magnetic thermal conductivity in hematite nanowires
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DOI：
10.1103/physrevb.104.245416
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发表时间：
2021-11
影响因子：
3.7
通讯作者：
Qing Xi;Adili Aiyiti;Lan Dong;Yuanyuan Wang;Jun Zhou;Xiangfan Xu
中科院分区：
文献类型：
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作者：
Qing Xi;Adili Aiyiti;Lan Dong;Yuanyuan Wang;Jun Zhou;Xiangfan Xu
磁相变点附近的热物理性质在临界现象的研究中具有重要意义。由于量纲诱导的量子约束和各向异性，低维材料具有不同于块状材料的热物理性质。在100K到150K的温度范围内，我们沿着[110]方向（生长方向）测量了α-Fe2O3纳米线的导热系数，发现在Morin温度附近导热系数有所下降。我们发现在Morin温度附近的导热系数随磁场与纳米线[110]方向夹角的变化而变化。更具体地说，由于磁场诱导磁畴壁的运动，观察到一个角相关的导热系数。根据磁各向异性能的计算，在Morin转变温度附近，由于磁易轴不同，导热系数最大值对应的角度不同。热导率的角度依赖性表明α-Fe2O3纳米线的易轴与体αFe2O3的几何各向异性不同。
The thermophysical properties near the magnetic phase transition point is of great importance in the study of critical phenomenon. Low-dimensional materials are suggested to hold different thermophysical properties comparing to their bulk counterpart due to the dimension induced quantum confinement and anisotropy. In this work, we measured the thermal conductivity of α-Fe2O3 nanowires along [110] direction (growing direction) with temperature from 100K to 150K and found a dip of thermal conductivity near the Morin temperature. We found the thermal conductivity near Morin temperature varies with the angle between magnetic field and [110] direction of nanowire. More specifically, an angular-dependent thermal conductivity is observed, due to the magnetic field induced movement of magnetic domain wall. The angle corresponding to the maximum of thermal conductivity varies near the Morin transition temperature, due to the different magnetic easy axis as suggested by our calculation based on magnetic anisotropy energy. This angular dependence of thermal conductivity indicates that the easy axis of α-Fe2O3 nanowires is different from bulk αFe2O3 due to the geometric anisotropy.