Irreversible magnetic-field dependence of low-temperature heat transport of spin-ice compound Dy 2 Ti 2 O 7 in a [111] field
Irreversible magnetic-field dependence of low-temperature heat transport of spin-ice compound Dy 2 Ti 2 O 7 in a [111] field
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[111]场中自旋冰化合物Dy 2 Ti 2 O 7 低温热传输的不可逆磁场依赖性
DOI：
10.1103/physrevb.87.144404
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发表时间：
2013
影响因子：
3.7
通讯作者：
X. Sun
中科院分区：
文献类型：
--
作者：
C. Fan;Z. Zhao;H. Zhou;X. M. Wang;Q. Li;F. Zhang;X. Zhao;X. Sun
研究了Dy_2Ti_2O_7沿（111）面和垂直于（111）面以及沿[111]方向磁场作用下的低温导热系数（\kappa）。在从自旋冰态到kagom - e-冰态再到极化态的场诱导转变过程中，除了\kappa呈阶梯状下降外，一个异常现象是，在上下扫磁场的情况下，\kappa(H)等温线在极低温度下表现出明显的不可逆性。令人惊讶的是，这种现象与众所周知的磁化迟滞现象没有对应关系。讨论了这种不可逆性的可能起源；特别地，提出了自旋冰化合物中磁单极子被弱无序所钉住的效应。
We study the low-temperature thermal conductivity (\kappa) of Dy_2Ti_2O_7 along and perpendicular to the (111) plane and under the magnetic field along the [111] direction. Besides the step-like decreases of \kappa at the field-induced transitions from the spin-ice state to the kagom\'e-ice state and then to the polarized state, an abnormal phenomenon is that the \kappa(H) isotherms show a clear irreversibility at very low temperatures upon sweeping magnetic field up and down. This phenomenon surprisingly has no correspondence with the well-known magnetization hysteresis. Possible origins for this irreversibility are discussed; in particular, a pinning effect of magnetic monopoles in spin ice compound by the weak disorders is proposed.