Kong Zhizhi, Kaminsky Corey J, Groschner Catherine K, Murphy Ryan A, Yu Yun, Husremović Samra, Xie Lilia S, Erodici Matthew P, Kim R Soyoung, Yano Junko, Bediako D Kwabena
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
J Am Chem Soc. 2023 Sep 13;145(36):20041-20052. doi: 10.1021/jacs.3c06967. Epub 2023 Aug 30.
Some magnetic systems display a shift in the center of their magnetic hysteresis loop away from zero field, a phenomenon termed exchange bias. Despite the extensive use of the exchange bias effect, particularly in magnetic multilayers, for the design of spin-based memory/electronics devices, a comprehensive mechanistic understanding of this effect remains a longstanding problem. Recent work has shown that disorder-induced spin frustration might play a key role in exchange bias, suggesting new materials design approaches for spin-based electronic devices that harness this effect. Here, we design a spin glass with strong spin frustration induced by magnetic disorder by exploiting the distinctive structure of Fe intercalated ZrSe, where Fe(II) centers are shown to occupy both octahedral and tetrahedral interstitial sites and to distribute between ZrSe layers without long-range structural order. Notably, we observe behavior consistent with a magnetically frustrated and multidegenerate ground state in these FeZrSe single crystals, which persists above room temperature. Moreover, this magnetic frustration leads to a robust and tunable exchange bias up to 250 K. These results not only offer important insights into the effects of magnetic disorder and frustration in magnetic materials generally, but also highlight as design strategy the idea that a large exchange bias can arise from an inhomogeneous microscopic environment without discernible long-range magnetic order. In addition, these results show that intercalated TMDs like FeZrSe hold potential for spintronic technologies that can achieve room temperature applications.
一些磁性系统的磁滞回线中心会偏离零场，这种现象被称为交换偏置。尽管交换偏置效应被广泛应用，尤其是在磁性多层膜中用于自旋基存储器/电子器件的设计，但对这种效应的全面机理理解仍然是一个长期存在的问题。最近的研究表明，无序诱导的自旋阻挫可能在交换偏置中起关键作用，这为利用这种效应的自旋基电子器件提出了新的材料设计方法。在这里，我们通过利用铁插层的ZrSe的独特结构设计了一种由磁无序诱导产生强自旋阻挫的自旋玻璃，其中Fe(II)中心占据八面体和四面体间隙位置，并在ZrSe层之间分布且没有长程结构有序。值得注意的是，我们在这些FeZrSe单晶中观察到与磁阻挫和多重简并基态一致的行为，这种行为在室温以上仍然存在。此外，这种磁阻挫导致高达250 K的强大且可调的交换偏置。这些结果不仅为一般磁性材料中磁无序和阻挫的影响提供了重要见解，还突出了一种设计策略，即大的交换偏置可以源于不均匀的微观环境而没有可辨别的长程磁有序。此外，这些结果表明像FeZrSe这样的插层过渡金属二卤化物在可实现室温应用的自旋电子技术中具有潜力。
