HfO2 films were produced by sputter deposition in the substrate temperature (Ts) range of room temperature (RT)-300°C and their structural, magnetic, and electrical properties were evaluated. The results indicate that the HfO2 films crystallize in the monoclinic structure and are oriented along the (-111) direction. Magnetization measurements (300-1.8 K) evidence their RT ferromagnetism. The effect of Ts is significant on the magnetic moment (M) and coercivity (Hc). M and Hc values enhanced with increasing Ts due to formation of oxygen vacancies. Increase in the temperature from 150 to 300 K decreases Hc without any transition, indicating that the Curie temperature of HfO 2 films is higher than RT. Electrical measurements indicate that the HfO2 films are semiconducting. © 2011 American Institute of Physics.