Ultrafast magnetism: The magneto-optical Kerr effect and conduction electrons

Abstract

Most experiments on ultrafast magnetodynamics have been conducted using the magneto-optical Kerr effect. Here, we compare the Kerr effect's magnetic sensitivity to the spin dynamics measured by photoemission. The magnetization dynamics on an Fe/W(110) thin film are probed by spin-resolved photoemission spectroscopy and the Kerr effect. The results reveal similarities between the spin dynamics at low binding energy and the response probed by the Kerr effect. Therefore, the Kerr effect probes states relevant for spin transport and spin flips but may not be sensitive to the entire magnetic moment in femtosecond spin dynamics experiments.

Ultrafast Demagnetization of Iron Induced by Optical versus Terahertz Pulses

“…(1) and Fig. S6), whose decay is a monitor of electron-phonon equilibration [20], and with results from time-resolved photoelectron spectroscopy [43].…”

Diagnostics of Nanosystems with the Use of Ultrashort X-Ray Pulses: Theory and Experiment (Brief Review)

“…A separate direction is the control of the state of various elements of micro-and nanoelectronics, including the study of ultrafast magnetization processes at the nanoscale. Using the magneto-optical Kerr effect, the authors of [123] performed such a study and compared the threshold sensitivity of the Kerr effect to the spin dynamics measured using photoemission for a Fe/W (110) thin film.…”

Ultrafast element-resolved magneto-optics using a fiber-laser-driven extreme ultraviolet light source

“…For the analysis of the raw asymmetry data, large energy regions around the M absorption edges were chosen: Fe between 50.7 and 54.5 eV and Ni between 63.4 and 67.5 eV. By integrating the off-diagonal component of the dielectric tensor over a wider energy range, we are less sensitive to spectrally distinct band-structure renormalization and population dynamics 9,10,17,[38][39][40][41] , and we effectively probe the element-specific magnetization. Already from the 1-hour dataset, we can easily resolve the delayed demagnetization dynamics between nickel and iron, as previously seen in Refs.…”