Fluorine doping inducing high temperature ferromagnetism in (In_(1-x)Fe_x)_2O_3

摘要

Fluorine (F) doping in (In_(1-x)Fe_x)_2O_3 was achieved by the process of a low temperature reaction with poly-vinylidene fluoride (PVDF). Ferromagnetism with a Curie temperature as high as 675 K was obtained in the F-doped (In_(1-x)Fe_x)_2O_3. It is found that F doping leads to reduction of Fe valence state from Fe~(3+) to Fe~(2+). The saturated magnetic moment (Ms) shows a maximum value when the ratio of Fe~(2+)/Fe~(3+) is 50%, indicating that the mixed-valence Fe~(2+)-Fe~(3+) pairs play an important role in inducing the ferromagnetism. Interestingly, it is further found that the ferromagnetism in the F-doped (In_(1-x)Fe_x)_2O_3 still exists even after high temperature annealing in air.