Spinel ferrite oxides doping non-magnetic ions show the photo-induced magnetization (PIM) effect at high temperature [1-3]. Such a magnetization enhancement by light irradiation is a unique property in this material. In order effectively to use the PIM effect and precisely to control the magnetism, direct light-emission from light-emitting element substrates would be a useful technique. In this study, spinel ferrite Al0.2Ru0.8Fe2O4 (ARFO) thin films, with the high temperature PIM effect, were prepared on GaAs(001) substrates by a pulsed laser deposition technique to aim integration with light-emitting devices based on GaAs lattice-matched materials in the future. Results showed that (001)-oriented ARFO thin films were successfully grown by using MgO buffer layers. The magnetic properties were approximately the same as ARFO films using other substrates such as Al2O3(0001) or MgO(001).