We report a photoinduced change of the coercive field, i.e., a photocoercivity effect (PCE), under very low intensity illumination of a low-doped (Ga,Mn)As ferromagnetic semiconductor. We find a strong correlation between the PCE and the sample resistivity. Spatially resolved dynamics of the magnetization reversal rule out any role of thermal heating in the origin of this PCE, and we propose a mechanism based on the light-induced lowering of the domain wall pinning energy. The PCE is local and reversible, allowing writing and erasing of magnetic images using light.
@article{arxiv.0810.4027,
title = {Non-thermal photocoercivity effect in a ferromagnetic semiconductor},
author = {G. V. Astakhov and H. Hoffmann and V. L. Korenev and T. Kiessling and J. Schwittek and G. M. Schott and C. Gould and W. Ossau and K. Brunner and L. W. Molenkamp},
journal= {arXiv preprint arXiv:0810.4027},
year = {2015}
}