A local view of the laser induced magnetic domain dynamics in CoPd stripe domains at the picosecond time scale

V López-Flores; M-A Mawass; J Herrero-Albillos; A A Uenal; S Valencia; F Kronast; C Boeglin

doi:10.1088/1361-648X/aba1ac

A local view of the laser induced magnetic domain dynamics in CoPd stripe domains at the picosecond time scale

J Phys Condens Matter. 2020 Aug 19;32(46). doi: 10.1088/1361-648X/aba1ac.

Authors

V López-Flores¹, M-A Mawass^{1

2}, J Herrero-Albillos^{2

3}, A A Uenal², S Valencia², F Kronast², C Boeglin¹

Affiliations

¹ Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France.
² Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
³ Centro Universitario de la Defensa, Zaragoza, Spain.

PMID: 32610298
DOI: 10.1088/1361-648X/aba1ac

Abstract

The dynamics of the magnetic structure in a well ordered ferromagnetic CoPd stripe domain pattern has been investigated upon excitation by femtosecond infrared laser pulses. Time-resolved x-ray magnetic circular dichroism in photoemission electron microscopy (TR-XMCD-PEEM) is used to perform real space magnetic imaging with 100 ps time resolution in order to show local transformations of the domains structures. Using the time resolution of the synchrotron radiation facility of the Helmholtz-Zentrum Berlin, we are able to image the transient magnetic domains in a repetitive pump and probe experiment. In this work, we study the reversible and irreversible transformations of the excited magnetic stripe domains as function of the laser fluence. Our results can be explained by thermal contributions, reducing the XMCD amplitude in each stripe domain below a threshold fluence of 12 mJ cm^-2. Above this threshold fluence, irreversible transformations of the magnetic domains are observed. Static XMCD-PEEM images reveal the new partially ordered stripe domain structures characterized by a new local magnetic domain distribution showing an organized pattern at the micrometer scale. This new arrangement is attributed to the recovery of the magnetic anisotropy during heat dissipation under an Oersted field.

Keywords: magnetic domains; magnetic order; spin dynamics.