Generation of Ultrafast Magnetic Steps for Coherent Control

• Main Authors: De Vecchi, G, Jotzu, G, Buzzi, M, Fava, S, Gebert, T, Fechner, M, Kimel, A, Cavalleri, A
• Format: Journal Article
• Language: English
• Published: 09-08-2024
• Subjects: Physics - Optics; Physics - Strongly Correlated Electrons; Physics - Superconductivity
• DOI: 10.48550/arxiv.2408.05153

A long-standing challenge in ultrafast magnetism and in functional materials
research in general, has been the generation of a universal, ultrafast stimulus
able to switch between stable magnetic states. Solving it would open up many
new opportunities for fundamental studies, with potential impact on 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, based on an ultrafast
quench of supercurrents in a superconductor. Magnetic field steps with
millitesla amplitude, picosecond risetimes and slew rates approaching 1 GT/s
are achieved. We test the potential of this technique by coherently rotating
the magnetization in a ferrimagnet. With suitable improvements in the geometry
of the device, these magnetic steps can be made both larger and faster, leading
to new applications that range from quenches across phase transitions to
complete switching of magnetic order parameters.