Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan.
Phys Rev Lett. 2019 Sep 13;123(11):117202. doi: 10.1103/PhysRevLett.123.117202.
Investigating exotic magnetic materials with spintronic techniques is effective at advancing magnetism as well as spintronics. In this work, we report unusual field-induced suppression of the spin Seebeck effect (SSE) in a quasi-one-dimensional frustrated spin-1/2 magnet LiCuVO_{4}, known to exhibit spin-nematic correlation in a wide range of external magnetic field B. The suppression takes place above |B|≳2 T in spite of the B-linear isothermal magnetization curves in the same B range. The result can be attributed to the growth of the spin-nematic correlation while increasing B. The correlation stabilizes magnon pairs carrying spin 2, thereby suppressing the interfacial spin injection of SSE by preventing the spin-1 exchange between single magnons and conduction electrons at the interface. This interpretation is supported by integrating thermodynamic measurements and theoretical analysis on the SSE.
用自旋电子技术研究奇异磁性材料在推进磁性和自旋电子学方面非常有效。在这项工作中，我们报告了在准一维受挫自旋 1/2 磁体 LiCuVO4 中观察到的异常磁场诱导的自旋塞贝克效应（SSE）的抑制，该材料在很宽的外磁场 B 范围内表现出自旋条纹相关。尽管在相同的 B 范围内存在 B 线性等温磁化曲线，但这种抑制发生在|B|≳2 T 以上。结果可以归因于自旋条纹相关性随 B 的增加而增强。这种相关性稳定了携带自旋 2 的磁子对，从而通过阻止界面上单磁子和传导电子之间的自旋 1 交换，抑制 SSE 的界面自旋注入。这一解释得到了 SSE 的热力学测量和理论分析的支持。
