Orbit-Engineered Anisotropic Magnetoresistive Effect for Constructing a Magnetic Sensor with Ultrahigh Sensitivity
Orbit-Engineered Anisotropic Magnetoresistive Effect for Constructing a Magnetic Sensor with Ultrahigh Sensitivity
复制标题
用于构建超高灵敏度磁传感器的轨道工程各向异性磁阻效应
DOI：
10.1021/acsami.1c24832
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发表时间：
2022
影响因子：
9.5
通讯作者：
Chun Feng
中科院分区：
文献类型：
--
作者：
Rong-Gui Zhu;Ling-Ran Yu;Xujie Ma;Q. X. Guo;Xiulan Xu;Chenchen Shi;Fei Meng;Baohe Li;Guanghua Yu;Chun Feng
由自旋-轨道耦合引起的强各向异性磁阻(AMR)效应是构建高灵敏度和高可靠性磁传感器的基础。目前，在传统薄膜中，有效的AMR增强主要集中在对晶格或电荷自由度的调制上，导致一般的AMR比率低于4%。在这里，我们演示了一种不同的策略，通过调节轨道自由度来加强AMR效应。通过在Ta/MgO/NiFe/MgO/Ta多层膜中插入一层氧亲和的Hf层，调制了MgO/NiFe界面上的Fe-O轨道杂化，从而引发了Fe的有效轨道重构。反过来，Fe的面内对称d轨道上的空穴数目显著增加，有利于S-d电子散射将AMR比提高到4.8%。通过进一步将薄膜加工成惠斯通电桥，我们构造了一种具有2.7mV/V/Oe超高灵敏度和0.8nT/√赫兹低噪声检测能力的传感元件。这些发现有助于推进轨道控制的AMR传感器的发展，并为调整其他与轨道有关的物理效应提供了一种替代方法。
A strong anisotropic magnetoresistance (AMR) effect induced by spin-orbit coupling is the basis for constructing a highly sensitive and reliable magnetic sensor. Presently, effective AMR enhancement in traditional films focuses on the modulation of the lattice or charge degree of freedom, leading to a general AMR ratio below 4%. Here, we demonstrate a different strategy to strengthen the AMR effect by tuning the orbital degree of freedom. By inserting an oxygen-affinitive Hf layer into a Ta/MgO/NiFe/MgO/Ta multilayer film, Fe-O orbital hybridization at the MgO/NiFe interface was modulated to trigger an effective orbital reconfiguration of Fe. In turn, the number of holes in the in-plane symmetric d orbits of Fe increased substantially, facilitating the s-d electron scattering to enhance the AMR ratio to 4.8%. By further micromachining the film into a Wheatstone bridge, we constructed a sensing element that displayed an ultrahigh sensitivity of 2.7 mV/V/Oe and a low noise detectability of 0.8 nT/√Hz. These findings help to advance the development of orbit-governed AMR sensors and provide an alternative method for tuning other orbit-related physical effects.