Ferromagnetism in Ga1-xMnxP: evidence for inter-Mn exchange mediated by   localized holes within a detached impurity band
  We demonstrate that in ferromagnetic Ga1-xMnxP exchange is mediated by holes localized in a Mn-derived band. For x<0.06, infrared absorption and photoconductivity spectra indicate the presence of a Mn impurity band which is not merged with the valence band. At temperatures above TC (<65 K) electrical transport is dominated by excitation across this energy gap while nearest neighbor hopping dominates below TC. Magnetization measurements reveal a moment of 3.5 Bohr magnetons per substitutional Mn, while the large anomalous Hall signal unambiguously demonstrates that the ferromagnetism is carrier-mediated. 
M.A. Scarpulla, B.L. Cardozo, W.M. Hlaing Oo, M.D. McCluskey, O.D.   Dubon