Room-temperature weak ferromagnetism of amorphous HfAlOx thin films deposited by pulsed laser deposition

The room-temperature weak ferromagnetism of amorphous HfAlOx thin films deposited by pulsed laser deposition on various substrates in oxygen-defective ambient is demonstrated. The magnetization is independent of film thickness, but depends on substrates and deposition temperatures. A magnetic moment of ∼0.26μB per HfAlOx f.u. is recorded for HfAlOx films deposited under optimized conditions [deposited at 600°C on (001) sapphire in high vacuum]. It is argued that interfacial defects are one of the possible sources of the weak ferromagnetism.