Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, Shaanxi, 710049, China.
Small. 2023 Jul;19(28):e2301955. doi: 10.1002/smll.202301955. Epub 2023 Mar 27.
Finding an energy-efficient way of switching magnetization is crucial in spintronic devices, such as memories. Usually, spins are manipulated by spin-polarized currents or voltages in various ferromagnetic heterostructures; however, their energy consumption is relatively large. Here, a sunlight control of perpendicular magnetic anisotropy (PMA) in Pt (0.8 nm)/Co (0.65 nm)/Pt (2.5 nm)/PN Si heterojunction in an energy-efficient manner is proposed. The coercive field (H ) is altered from 261 to 95 Oe (64% variation) under sunlight illumination, enabling a nearly 180° deterministic magnetization switching reversibly with a 140 Oe magnetic bias assistant. The element-resolved X-ray circular dichroism measurement reveals different L3 and L2 edge signals of the Co layer with or without sunlight, suggesting a photoelectron-induced redistribution of the orbital and spin moment in Co magnetization. The first-principle calculations also reveal that the photo-induced electrons shift the Fermi level of electrons and enhance the in-plane Rashba field around the Co/Pt interfaces, leading to a weakened PMA and corresponding H decreasing and magnetization switching accordingly. The sunlight control of PMA may provide an alternative way for magnetic recording, which is energy efficient and would reduce the Joule heat from the high switching current.
在自旋电子器件（如存储器）中，找到一种节能的磁化切换方式至关重要。通常，自旋通过各种铁磁异质结构中的自旋极化电流或电压来操纵；然而，它们的能量消耗相对较大。在这里，提出了一种以节能的方式用光来控制 Pt（0.8nm）/Co（0.65nm）/Pt（2.5nm）/PN Si 异质结中垂直磁各向异性（PMA）的方法。在阳光照射下，矫顽场（H）从 261 变为 95 Oe（64%的变化），在 140 Oe 磁偏置辅助下，可以实现近乎 180°的确定性磁化反转。元素分辨 X 射线圆二色性测量表明 Co 层在有或没有阳光照射时有不同的 L3 和 L2 边缘信号，这表明光电诱导的 Co 磁化轨道和自旋矩重新分布。第一性原理计算还表明，光致电子使电子的费米能级移动，并增强 Co/Pt 界面周围的平面 Rashba 场，导致 PMA 减弱，相应的 H 减小，磁化随之反转。PMA 的光控可能为磁记录提供一种替代方法，这种方法既节能又能减少高切换电流产生的焦耳热。
