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Fe-doped HfO2 thin films are room temperature ferromagnetic. In comparison with results of the undoped HfO2 films, it seems that the Fe doping is not the main cause for the ferromagnetism but only acts as a catalyst. Experimental results of oxygen annealing and vacuum heat treatments have proven that in this family of compounds, magnetism might originate from oxygen vacancies or defects. Removing oxygen enhances the magnetic moment, while reversibly filling up oxygen vacancies can destroy the ferromagnetic ordering of the system.

Laser ablated Ni-doped HfO_2 thin films fabricated under a wide range of growth conditions all showed ferromagnetism above room temperature. However, the films deposited at 800 °C under an oxygen partial pressure of 10^ Torr have the largest magnetic moment of 2.7μB/ Ni. Ni-doped HfO_2 films also well demonstrate a large anisotropy. Magnetic force microscopy measurements confirmed that Ni-doped HfO2 films are real room temperature ferromagnets with a domain structure, and that the size of magnetic domains is larger than 10 μm.