Niu Yuting, Liu Zhen, Wang Ke, Ai Wanlei, Gong Tao, Liu Tao, Bi Lei, Zhang Gang, Deng Longjiang, Peng Bo
National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China.
Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China.
Adv Mater. 2024 Nov;36(46):e2403066. doi: 10.1002/adma.202403066. Epub 2024 Sep 30.
Controlling exchange bias (EB) by electric fields is crucial for next-generation magnetic random access memories and spintronics with ultralow energy consumption and ultrahigh speed. Multiferroic heterostructures have been traditionally used to electrically control EB and interfacial ferromagnetism through weak/indirect coupling between ferromagnetic and ferroelectric films. However, three major bottlenecks (lattice mismatch, interface defects, and weak/indirect coupling in multiferroic heterostructures) remain, resulting in only a few tens of milli-tesla EB field. Here, this study reports a robust electric-field control recipe to dynamically tailor the EB effect in a pure CrI homotrilayer on a ferroelectric Y-doped HfO (HYO) substrate, and demonstrate a colossal and tunable EB field (H) from -0.15 to +0.33 T, giving rise to an EB modulation of 0.48 T. The charge doping due to ferroelectric HYO film divides a homo-configuration of CrI homotrilayer into one antiferromagnetic (AFM) bilayer CrI and one ferromagnetic (FM) monolayer CrI, favoring direct exchange coupling. The synergies of charge doping and electric field induce a transition of magnetic orders from AFM to FM phase in bilayer CrI, which is also supported by first-principles calculations, leading to the robust electric control of colossal EB effect. The results therefore open numerous opportunities for exploring 2D spintronics, memories, and braininspired in-memory computing.
通过电场控制交换偏置（EB）对于下一代具有超低能耗和超高速的磁随机存取存储器和自旋电子学至关重要。传统上，多铁性异质结构已被用于通过铁磁和铁电薄膜之间的弱/间接耦合来电控制EB和界面铁磁性。然而，三个主要瓶颈（晶格失配、界面缺陷以及多铁性异质结构中的弱/间接耦合）仍然存在，导致EB场仅为几十毫特斯拉。在此，本研究报告了一种强大的电场控制方法，用于动态调整铁电Y掺杂HfO（HYO）衬底上纯CrI同质三层中的EB效应，并展示了从-0.15到+0.33 T的巨大且可调的EB场（H），产生了0.48 T的EB调制。铁电HYO薄膜引起的电荷掺杂将CrI同质三层的同构配置分为一个反铁磁（AFM）双层CrI和一个铁磁（FM）单层CrI，有利于直接交换耦合。电荷掺杂和电场的协同作用在双层CrI中诱导磁序从AFM相转变为FM相，这也得到了第一性原理计算的支持，从而实现了对巨大EB效应的强大电控制。因此，这些结果为探索二维自旋电子学、存储器和受脑启发的内存计算开辟了众多机会。
