The effect of annealing on the room temperature ferromagnetism in co-sputtered In2O3: C thin films

In this paper, we report investigation of room temperature (RT) ferromagnetism in In2O3 (InO) thin films doped with carbon prepared by the co-sputtering method. InO thin films both undoped and C doped with varied thicknesses in the range of 45 to 80 nm were synthesized on Si substrates with varied C concentrations. The carbon concentration was varied from 1.6 to 9.3 at%. The undoped InO films showed no trace of ferromagnetism. Carbon doped films (InO:C) exhibited ferromagnetism at RT, which was of the orders of 10−5 emu and varied strongly with C concentrations. It is observed that the magnetization reached a maximum value of 5.7 emu/cm3 at 4 at% C. Annealing of the InO:C films in an oxygen environment resulted in a decrease in the magnetization, indicating the crucial role of oxygen vacancies in the films. It is concluded that the oxygen vacancies were important and compete with C substitution for the RT ferromagnetism.

► Synthesis of carbon doped In2O3 thin films using co-sputtering technique.
► Effect of C concentration on room temperature ferromagnetism.
► Role of annealing in oxygen environment on carbon doped In2O3.
► Effect of substrates on magnetic properties of InO:C thin films.
► Role of oxygen vacancies and its competition with C doping.