Exchange bias without directional anisotropy in permalloy/CoO bilayers
Exchange bias without directional anisotropy in permalloy/CoO bilayers
复制标题
DOI：
10.1103/physrevb.104.144413
复制
发表时间：
2021-10-14
影响因子：
3.7
通讯作者：
Urazhdin, Sergei
中科院分区：
文献类型：
--
作者：
Mitrofanov, Alexander;Chen, Guanxiong;Urazhdin, Sergei
我们利用横向交流磁化率测量来表征铁磁铁permalloy （Py）和反铁磁铁CoO的典型交换偏压双层中的磁各向异性。单向各向异性在较薄的Py中被观察到，但在较大的Py厚度下可以忽略不计，即使磁滞回线的方向不对称性仍然很明显。额外的磁阻测量、磁光成像以及微磁模拟表明，这些令人惊讶的行为可能与Py磁化逆转过程中CoO中自旋翻转分布的不对称性有关，这有助于后者旋转回其场冷方向。我们的发现为神经形态应用的多稳态纳米磁系统的有效实现提供了可能性
We utilize transverse ac susceptibility measurements to characterize magnetic anisotropy in archetypal exchange-bias bilayers of ferromagnet permalloy (Py) and antiferromagnet CoO. Unidirectional anisotropy is observed for thin Py but becomes negligible at larger Py thicknesses, even though the directional asymmetry of the magnetic hysteresis loop remains significant. Additional magnetoresistance measurements, magneto-optical imaging, as well as micromagnetic simulations show that these surprising behaviors are likely associated with asymmetry of spin-flop distribution created in CoO during Py magnetization reversal, which facilitates the rotation of the latter back into its field-cooled direction. Our findings suggest possibilities for efficient realization of multistable nanomagnetic systems for neuromorphic applications