Intra-well relaxation process in magnetic fluids subjected to strong polarising fields

► Intra-well relaxation process in a magnetic fluid is studied. ► Sample consists of the tetragonal phase of maghemite and magnetite particles. ► A subsidiary relaxation peak is observed in the vicinity of the resonance peak. ► Relaxation peak is correlated to the intra-well relaxation process. ► It is assigned to the tetragonal phase of maghemite particles.