Ultrafast Demagnetization Dynamics at the M Edges of Magnetic Elements Observed Using a Tabletop High-Harmonic Soft X-Ray Source

Published

December 15, 2009

Author(s)

Thomas J. Silva, Justin Shaw, Hans Nembach, Chan La-O-Vorakiat, Mark Siemens, Margaret M. Murnane, Henry C. Kapteyn, Stefan Mathias, Martin Aeschlimann, Patrik Grychtol, Roman Adam, Claus M. Schneider

Abstract

We use few-femtosecond soft x-ray pulses from high-harmonic generation to extract element-specific demagnetization dynamics and hysteresis loops of a compound material for the first time. Using a geometry where high-harmonic beams are reflected from a magnetized Permalloy grating, large changes in the reflected intensity of up to 6% at the M absorption edges of Fe and Ni are observed when the magnetization is reversed. A short pump pulse is used to destroy the magnetic alignment, which allows us to measure the fastest, elementally specific demagnetization dynamics, with 55 fs time resolution. The use of high harmonics for probing magnetic materials promises to combine nanometer spatial resolution, elemental specificity, and femtosecond-to-attosecond time resolution, making it possible to address important fundamental questions in magnetism.

Citation

Physical Review Letters

Volume

103

Issue

25

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevLett.103.257402

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Keywords

high harmonic generation, transverse magneto-optic Kerr effect, Permalloy, soft x-ray, M absorption edge, T-MOKE

Citation

Silva, T. , Shaw, J. , Nembach, H. , La-O-Vorakiat, C. , Siemens, M. , Murnane, M. , Kapteyn, H. , Mathias, S. , Aeschlimann, M. , Grychtol, P. , Adam, R. and Schneider, C. (2009), Ultrafast Demagnetization Dynamics at the M Edges of Magnetic Elements Observed Using a Tabletop High-Harmonic Soft X-Ray Source, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.103.257402, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=902752 (Accessed September 23, 2025)