交换偏置效应在现代磁存储技术中至关重要。面向器件小型化与多功能集成，实现室温以上、可调的全二维交换偏置成为关键挑战。近日，我们联合ETH丁石磊博士、华南师范大学侯志鹏教授、中山大学侯仰龙教授及北京大学罗昭初助理教授，首次在全范德瓦尔斯反铁磁/铁磁异质结(Fe_0.56Co_0.44)₅GeTe₂（FCGT）/Fe₃GaTe₂（FGaT）中实现了室温可重构的垂直交换偏置效应。研究发现，该效应可由预设场直接诱导，无需传统场冷工艺，阻塞温度达300 K。通过外场调控反铁磁FCGT的奈尔序，可精准操控交换偏置场的符号与强度。我们发现预设场可诱导奈尔矢量翻转，促使界面磁矩对齐，从而产生稳固的交换偏置状态，和理论模型结果一致。该机制揭示了奈尔序调控在二维磁界面工程中的核心作用，为开发新型低维自旋电子器件提供了新见解。

  Exchangebias (EB) effect is crucial in modern magnetic storage technology. With device miniaturization and multifunctional integration, achieving tunable all-van der Waals exchange bias above room temperature is challenging. Recently, in collaboration with Dr. Shilei Ding at ETH, Prof. Zhipeng Hou at South China Normal University, Prof. Yanglong Hou at Sun Yat-sen University, and Prof. Zhaochu Luo at Peking University, we realized reconfigurable perpendicular exchange bias at room temperature in a van der Waals antiferromagnet/ferromagnet heterostructure: (Fe_0.56Co_0.44)₅GeTe₂（FCGT）/Fe₃GaTe₂（FGaT）. Our study shows that EB effect in this system is directly induced by a preset field without traditional field-cooling process, with a blocking temperature of 300 K. By tuning Néel order of FCGT via external magnetic field, the sign and magnitude of the EB field are precisely controlled: A strong pre-set field induces a switch in the Néel order of FCGT, which aligns the interfacial magnetization at the FCGT/FGaT interface, leading to robust EB. This mechanism reveals the key role of Néel order regulation in two-dimensional magnetic interface engineering, offering new insights for low-dimensional spintronic devices.

图1 全二维异质结FCGT/FGaT中室温可重构的交换偏置

  相关成果已经发表于《ACS Nano》，论文第一作者为22级博士研究生王继承。论文链接：https://pubs.acs.org/doi/10.1021/acsnano.5c08572