Implantation of Mn or Cr at doses of 3-5 x 10(16) cm(-2) into Si-doped Al0.24Ga0.76P epilayers on Gad substrates produced ferromagnetic ordering at temperatures up to 300 K. The results were similar to those obtained previously in p-type AlGaP(C), indicating that both electron and hole-doped AlGaP can exhibit ferromagnetism. In addition, the AlGaP results are similar to those for Gad so the magnitude of the bandgap was not the main parameter influencing the Curie temperature, in contradiction to predictions from some mean-field theories. Second phases were not observed by X-ray diffraction and were not responsible for the ferromagnetism. (C) 2003 Elsevier Science Ltd. All rights reserved.