ISSN - 00036951, EISSN - 10773118, Applied Physics Letters, 2015, vol. 107, 12, p. -
Ferromagnetic HfO<inf>2</inf>/Si/GaAs interface for spin-polarimetry applications
© 2015 AIP Publishing LLC. In this letter, we present electrical and magnetic characteristics of HfO<inf>2</inf>-based metal-oxide-semiconductor capacitors (MOSCAPs), along with the effect of pseudomorphic Si as a passivating interlayer on GaAs(001) grown by molecular beam epitaxy. Ultrathin HfO<inf>2</inf> high-k gate dielectric films (3-15 nm) have been grown on Si/GaAs(001) structures through evaporation of a Hf/HfO<inf>2</inf> target in NO<inf>2</inf> gas. The lowest interface states density Dit at Au/HfO<inf>2</inf>/Si/GaAs(001) MOS-structures were obtained in the range of (6-13)×1011 eV<sup>-1</sup> cm<sup>-2</sup> after annealing in the 400-500 °C temperature range as a result of HfO<inf>2</inf> crystallization and the Si layer preservation in non-oxidized state on GaAs. HfO<inf>2</inf>-based MOSCAPs demonstrated the ferromagnetic properties which were attributed to the presence of both cation and anion vacancies according to the first-principle calculations. Room-temperature ferromagnetism in HfO<inf>2</inf> films allowed us to propose a structure for the ferromagnetic MOS spin-detector.