Alternating layers of granular Iron (Fe) and Titanium dioxide (TiO2−δ) were deposited on (100) Lanthanum aluminate (LaAlO3) substrates in low oxygen chamber pressure using a controlled pulsed laser ablation deposition technique. The total thickness of the film was about 200 nm. The films show ferromagnetic behavior for temperatures ranging from 4 to 400oK. The layered film structure was characterized as p-type magnetic semiconductor at 300oK with a carrier density of the order of 1020/cm3. The undoped pure TiO2−δ film was characterized as an n-type magnetic semiconductor. The hole carriers were excited at the interface between the granular Fe and TiO2−δ layers similar to holes excited in the metal/n-type semiconductor interface commonly observed in Metal-Oxide-Semiconductor (MOS) devices. The holes at the interface were polarized in an applied magnetic field raising the possibility that these granular MOS structures can be utilized for practical spintronic device applications.
@article{arxiv.0705.2993,
title = {Room temperature spin polarized magnetic semiconductor},
author = {Soack Dae Yoon and Carmine Vittoria and Vincent G. Harris and Allan Widom},
journal= {arXiv preprint arXiv:0705.2993},
year = {2007}
}