Laser-induced magnetization dynamics in a cobalt/garnet heterostructure

¹ Laboratory of Magnetism, Faculty of Physics, University of Bialystok - Lipowa 41, 15-424 Bialystok, Poland
² Radboud University Nijmegen, Institute for Molecules and Materials - Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
³ Scientific-Practical Materials Research Centre of the NASB - P. Brovki 19, 220072 Minsk, Belarus

^(a) and@uwb.edu.pl

Received: 16 October 2013
Accepted: 19 January 2014

Abstract

We report on magnetization dynamics triggered in a Co/garnet heterostructure by femtosecond laser pulses. Although laser excitation of a bare Co-doped yttrium iron garnet leads to magnetization precession, the phase of which strongly depends on the linear polarization of the light pulses, the deposition of an ultrathin Co layer on a top of a garnet film results in substantial changes of the laser-induced dynamics. The precession in the garnet is shown to lose its sensitivity to the polarization. Instead, light triggers polarization insensitive precession in both the magnetostatically coupled Co layer and the garnet film at two distinct frequencies typical for Co and garnet layers.