The role of magnetic polarons in ferromagnetic GdN
  We report an interplay between magnetism and charge transport in the ferromagnetic semiconductor GdN, pointing to the formation of magnetic polarons centred on nitrogen vacancies. The scenario goes some way to resolving a long-standing disagreement between the measured and predicted Curie temperature in GdN. It further constitutes an extension of concepts that relate closely to the behaviour of ferromagnetic semiconductors generally, and EuO in particular. 
Franck Natali, Ben Ruck, Joe Trodahl, Do Le Binh, Stephane Vezian,   Benjamin Damilano, Yvon Cordier, Fabrice Semond, and Cl...
cond-mat.str-el