  The main obstacles in realizing diluted magnetic oxide (DMO) in spintronics
are the unknown electronic structures associated with its high TC
ferromagnetism and spin polarized current and how to manipulate desired
electronic structures by fabrication techniques. We demonstrate that fine-tuned
electronic structures and band structures can be modified to initiate DMO
properties. Interestingly, in the semiconducting state, the doped Co ions and
oxygen vacancies contribute non-negligible magnetic moments; and the magnetic
coupling between these moments is mediated by the localized carriers via highly
spin polarized hopping transport. These results unravel the myth of the origin
of spintronic characteristics with desirable electronic states; thereby
reopening the door for future applications.
