Song Yixuan, Nguyen Thanh, Li Mingda, Ross Caroline A, Beach Geoffrey S D
Department of Materials Science and Engineering, MIT, Cambridge, MA 02139, USA.
Department of Nuclear Science and Engineering, MIT, Cambridge, MA 02139, USA.
Sci Adv. 2025 Aug 22;11(34):eadu7725. doi: 10.1126/sciadv.adu7725.
Writing magnetic bits through spin-orbit torque (SOT) switching is promising for fast and efficient magnetic random-access memory devices. While SOT switching of out-of-plane (OOP) magnetized states requires lateral symmetry breaking, in-plane (IP) magnetized states suffer from low storage density. Here, we demonstrate a field-free switching scheme using a 5-nanometer europium iron garnet film grown with a (110) orientation that shows a spin reorientation transition from OOP to IP above room temperature. This scheme combines the benefits of high-density storage in the OOP states at room temperature and the efficient field-free SOT switching in the IP states at elevated temperatures. While conventional switching of OOP bits faces the dilemma that high OOP anisotropy is required to improve bit stability and low OOP anisotropy is required to lower switching current density, this scheme disentangles this interdependence, allowing for low switching currents to be possible without sacrificing the bit stability, offering opportunities for future memory devices.
通过自旋轨道扭矩（SOT）切换来写入磁比特，对于快速高效的磁随机存取存储设备而言颇具前景。虽然面外（OOP）磁化状态的SOT切换需要横向对称性破缺，但面内（IP）磁化状态存在存储密度低的问题。在此，我们展示了一种无场切换方案，该方案使用生长为（110）取向的5纳米铕铁石榴石薄膜，其在室温以上表现出自旋重取向转变，即从OOP转变为IP。此方案结合了室温下面外状态的高密度存储优势以及高温下面内状态的高效无场SOT切换优势。传统的面外比特切换面临两难困境：提高比特稳定性需要高面外各向异性，而降低切换电流密度则需要低面外各向异性，该方案解开了这种相互依存关系，使得在不牺牲比特稳定性的情况下实现低切换电流成为可能，为未来的存储设备提供了机遇。
