A study of room-temperature ferromagnetism in transition metal and fluorine-doped spray-pyrolyzed SnO2 thin films

Room-temperature ferromagnetism has been observed in Co- or Mn-doped SnO2 and Co- and F-co-doped SnO2 thin films. A maximum magnetic moment of 0.80μB/Co ion has been observed for Sn0.90Co0.10O1.925−δF0.075 thin films, whereas in the case of Sn1−xMnxO2−δ it was 0.18μB/Mn ion for x=0.10. The magnetization of both Sn1−xCoxO2−δ and Sn1−xCoxO2−y−δFy thin films depends on the free carrier concentration. An anomalous Hall effect has been observed in the case of Co-doped SnO2 films. However, the same was not observed in the case of Mn-doped SnO2 thin films. Carrier-mediated interaction is convincingly proved to be the cause of ferromagnetism in the case of Co:SnO2. It is, however, proposed that no carrier-mediated interaction exists in the case of Mn:SnO2. Present studies indicate that dopants and hence electronic cloud-lattice interaction plays an important role in inducing ferromagnetism.