The structural and magnetic properties of phase-separated (Ga, Mn)As granular material, obtained by annealing diluted (Ga, Mn)As grown by molecular-beam epitaxy at low temperature, are investigated using transmission electron microscopy, high-resolution X-ray diffraction, and superconducting quantum interference device magnetometry. Synthesis strategies are defined to achieve specific magnetic properties through the control of the material structure. (C) 2004 Elsevier B.V. All rights reserved.