2025年4月2日出版的《自然—光子学》杂志发表了德国马克斯·普朗克物质结构与动力学研究所Cavalleri, A.研究小组的最新成果，他们提出了生成用于相干控制的超快磁阶跃。

一般来说，超快磁性和功能材料研究中的一个长期挑战是产生能够在稳定磁性状态之间切换的通用超快刺激。解决这个问题将为基础研究开辟许多新的机会，可能会影响未来的数据存储技术。理想情况下，具有无限快上升时间的阶梯状磁场瞬变将达到这一目的。

研究组开发了一种通过淬灭超导体中的超电流来产生超快磁场阶跃的新方法。他们实现了具有毫特斯拉振幅、皮秒上升时间和接近1 GT s^-1的转换速率的磁场阶跃。通过相干旋转亚铁磁体中的磁化来测试这项技术的潜力。尽管在当前的几何形状中，磁场步长不足以实现完全切换，但器件几何形状的适当改进可以使这些磁步长更大更快。研究组预见到新的应用，从跨相变的淬火到磁序参数的完全切换。

附：英文原文

Title: Generation of ultrafast magnetic steps for coherent control

Author: De Vecchi, G., Jotzu, G., Buzzi, M., Fava, S., Gebert, T., Fechner, M., Kimel, A. V., Cavalleri, A.

Issue&Volume: 2025-04-02

Abstract: A long-standing challenge in ultrafast magnetism and functional materials research, in general, has been the generation of a universal, ultrafast stimulus able to switch between stable magnetic states. Solving this problem would open up many new opportunities for fundamental studies, potentially impacting future data storage technologies. Ideally, step-like magnetic field transients with infinitely fast rise time would serve this purpose. Here we develop a new approach to generate ultrafast magnetic field steps by quenching supercurrents in a superconductor. We achieve magnetic field steps with millitesla amplitude, picosecond rise times and slew rates approaching 1GTs–1. We test the potential of this technique by coherently rotating the magnetization in a ferrimagnet. Although in the current geometry, the magnetic field step is not sufficient to achieve complete switching, suitable improvements in the device geometry could make these magnetic steps both larger and faster. We foresee new applications ranging from quenches across phase transitions to complete switching of magnetic order parameters.

DOI: 10.1038/s41566-025-01651-y

Source: https://www.nature.com/articles/s41566-025-01651-y