Magnetic freezing transition in a CoO/Permalloy bilayer revealed by transverse ac susceptibility
Magnetic freezing transition in a CoO/Permalloy bilayer revealed by transverse ac susceptibility
复制标题
横向交流磁化率揭示 CoO/坡莫合金双层的磁冻结转变
DOI：
10.1016/j.jmmm.2018.12.056
复制
发表时间：
2018
影响因子：
2.7
通讯作者：
L. Novozhilova
中科院分区：
文献类型：
--
作者：
S. Urazhdin;Weijie Li;L. Novozhilova
利用变温、变频磁光横向磁化率技术研究了CoO/坡莫合金双层薄膜的静态和动态磁性。我们的测量结果表明，在所研究的系统中，磁滞回线的方向不对称性主要与交换诱导单轴各向异性稳定的磁化的两个反转状态之间的反转机制的差异。后者被发现是远远大于交换诱导的铁磁体的单向各向异性。我们还观察到交流磁化率的频率依赖的虚部附近的交换偏置阻断温度的突然变化，从以前的时域研究推断在类似的系统中的磁老化的磁冻结转变相一致。所开发的测量方法能够精确表征薄膜磁性异质结构的动态和静态特性，可以在可重构磁振子和神经形态电路中找到应用。
We utilize variable-temperature, variable-frequency magneto-optical transverse magnetic susceptibility technique to study the static and dynamical magnetic properties of a thin-film CoO/Permalloy bilayer. Our measurements demonstrate that in the studied system, the directional asymmetry of the hysteresis loop is associated mainly with the difference in the reversal mechanisms between the two reversed states of magnetization stabilized by the exchange-induced uniaxial anisotropy. The latter is found to be much larger than the exchange-induced unidirectional anisotropy of the ferromagnet. We also observe an abrupt variation of the frequency-dependent imaginary part of ac susceptibility near the exchange bias blocking temperature, consistent with the magnetic freezing transition inferred from the previous time-domain studies of magnetic aging in similar systems. The developed measurement approach enables precise characterization of the dynamical and static characteristics of thin-film magnetic heterostructures that can find applications in reconfigurable magnonic and neuromorphic circuits.