Nontrivial temperature dependence of ferromagnetic resonance frequency for spin reorientation transitions
Nontrivial temperature dependence of ferromagnetic resonance frequency for spin reorientation transitions
复制标题
DOI：
10.1103/physrevb.100.020403
复制
发表时间：
2019-07
影响因子：
3.7
通讯作者：
M. Nishino;S. Miyashita
中科院分区：
文献类型：
--
作者：
M. Nishino;S. Miyashita
我们发现自旋-再取向(SR)转变的铁磁共振(FMR)频率异常地依赖于温度，其中易轴随温度而变化，在ND永磁体中观察到，在自旋-再取向转变温度($T\rM R}$)以下，Nd2$Fe${14}$B：$f\rM R}\sim 0$，在$T{\rM R}$附近急剧增加$f{\rM}$，并在较高温度下从峰值下降。SR转变导致铁磁共振频率在很宽的温度范围内出现异常行为，这不是一件微不足道的事。通过理论和计算分析，揭示了温度依赖的机理。我们推导出了fRmR与磁化强度之间的一般关系，以帮助理解这一机制，并阐明横向磁化强度的涨落是在所有温度区域发生共振的关键因素。
We find unusual temperature dependence of the ferromagnetic resonance (FMR) frequency $f_{\rm R}$ for the spin-reorientation (SR) transition, in which the easy axis changes depending on temperature, observed in the Nd permanent magnet, Nd$_2$Fe$_{14}$B: $f_{\rm R} \sim 0$ below the SR transition temperature ($T_{\rm R}$), drastic increase of $f_{\rm R}$ around $T_{\rm R}$, and decrease from a peak at higher temperatures. It is nontrivial that the SR transition causes the unusual behavior of the FMR frequency in a wide temperature region. We show the mechanism of the temperature dependence by theoretical and computational analyses. We derive a general relation between $f_{\rm R}$ and magnetizations to help the understanding of the mechanism, and clarify that the fluctuation of the transverse magnetization is a key ingredient for the resonance in all temperature regions.