Spin dynamics triggered by sub-terahertz magnetic field pulses

TL;DR

This paper demonstrates the generation of sub-terahertz magnetic field pulses using photoconductive switches and investigates their effect on magnetic excitations in Fe microstructures through time-resolved Kerr spectroscopy and simulations.

Contribution

It introduces a method to generate and calibrate ultrafast THz magnetic pulses and studies their immediate impact on magnetic materials.

Findings

Magnetic field pulses of 0.6 Tesla are generated with 3 ps duration.

Magnetic excitations in Fe microstructures respond within less than 10 ps.

Experimental results agree with micromagnetic simulations.

Abstract

Current pulses of up to 20 A and as short as 3 ps are generated by a low temperature grown GaAs (lt-GaAs) photoconductive switch and guided through a coplanar waveguide, resulting in a 0.6 Tesla terahertz (THz) magnetic field pulse. The pulse length is directly calibrated using photocurrent autocorrelation. Magnetic excitations in Fe microstructures are studied by time-resolved Kerr spectroscopy and compared with micromagnetic simulations. A response within less than 10 ps to the THz electromagnetic field pulse is found.