论文标题
单个铁磁层中的大型单向磁性
Large anomalous unidirectional magnetoresistance in a single ferromagnetic layer
论文作者
论文摘要
由于自旋霍尔效应（SHES），在铁磁双层中的单向磁磁性（UMR）提供了一种简单的探测面内磁化的手段，以避免复杂的磁性隧道连接。但是，UMR信号非常弱，通常需要一个锁定放大器才能检测，即使在涉及具有较大旋转厅角（SHA）的TA或PT的双层中。在这里，我们报告了一种类型的UMR，称为异常的UMR（AUMR），在单个COFEB层中没有任何相邻的层，其中UMR信号比TA/COFEB结构中的UMR信号大约10倍，并且可以在缺乏锁定放大器的情况下使用常规的DC Multimeters在TA/COFEB结构中大。我们进一步证明，通过排除热贡献提取的AUMR表明，COFEB和Nife单层具有相反SHA的逆转迹象，表明AUMR可能源自通过巨型磁磁性的磁磁性机制与磁化相互作用的自生旋转的旋转积累。这些结果表明，AUMR贡献了UMR信号大于COFEB涉及系统中的界面自旋霍尔UMR，从而提供了一种方便可靠的方法来检测两端自旋设备的面内磁化。
Unidirectional magnetoresistance (UMR) in a ferromagnetic bilayer due to the spin Hall effects (SHEs) provides a facile means of probing in-plane magnetization to avoid complex magnetic tunnel junctions. However, the UMR signal is very weak and usually requires a lock-in amplifier for detection even in the bilayer involving Ta or Pt with a large spin Hall angle (SHA). Here we report a type of UMR, termed as the anomalous UMR (AUMR), in a single CoFeB layer without any adjacent SHE layers, where the UMR signal is about 10 times larger than that in Ta/CoFeB structures and can be detected by using conventional dc multimeters in the absence of lock-in amplifiers. We further demonstrate that the extracted AUMR by excluding thermal contributions shows reversal signs for the CoFeB and NiFe single layers with opposite SHAs, indicating that the AUMR may originate from the self-generated spin accumulation interacting with magnetization through the giant magnetoresistance-like mechanism. These results suggest that the AUMR contributes UMR signals larger than the interfacial spin Hall UMR in the CoFeB-involved systems, providing a convenient and reliable approach to detect in-plane magnetization for the two-terminal spintronic devices.
