Hu Shaojie, Cui Xiaomin, Yue Zengji, Wang Pangpang, Ohnishi Kohei, Wu Shu-Qi, Su Sheng-Qun, Sato Osamu, Yamada Sunao, Kimura Takashi
Department of Physics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China.
Nano Lett. 2024 Jun 12;24(23):6924-6930. doi: 10.1021/acs.nanolett.4c01031. Epub 2024 May 31.
We have experimentally investigated the mechanism of the exchange bias in 2D van der Waals (vdW) ferromagnets by means of the anomalous Hall effect (AHE) together with the dynamical magnetization property. The temperature dependence of the AC susceptibility with its frequency response indicates a glassy transition of the magnetic property for the Te-rich FeGeTe vdW ferromagnet. We also found that the irreversible temperature dependence in the anomalous Hall voltage follows the de Almeida-Thouless line. Moreover, the freezing temperature of the spin-glass-like phase is found to correlate with the disappearance temperature of the exchange bias. These important signatures suggest that the emergence of magnetic exchange bias in the 2D van der Waals ferromagnets is induced by the presence of the spin-glass-like state in FeGeTe. The unprecedented insights gained from these findings shed light on the underlying principles governing exchange bias in vdW ferromagnets, contributing to the advancement of our understanding.
我们通过反常霍尔效应（AHE）以及动态磁化特性，对二维范德华（vdW）铁磁体中的交换偏置机制进行了实验研究。交流磁化率随温度的变化及其频率响应表明，富碲FeGeTe范德华铁磁体的磁性发生了玻璃态转变。我们还发现，反常霍尔电压中不可逆的温度依赖性遵循德阿尔梅达 - 索利斯线。此外，发现类自旋玻璃相的冻结温度与交换偏置的消失温度相关。这些重要特征表明，二维范德华铁磁体中磁交换偏置的出现是由FeGeTe中类自旋玻璃态的存在所诱导的。从这些发现中获得的前所未有的见解揭示了范德华铁磁体中交换偏置的潜在原理，有助于增进我们的理解。
