Abstract:

Diluted magnetic oxides (DMO) with a ferromagnetic transition temperature,T _c , far above room temperature seem open a promising for spintronic applications.  However, the relatively weak ferromagnetic ordering and low ratio of spin current in such materials have limited their applications.  Therefore, the detailed mechanisms of magnetic coupling and electric conduction in DMOs need further study before they can be applied in spintronics. Unfortunately, the mechanism of magnetic coupling and electric conduction for DMOs are not clear at this time.  RKKY and BMP models can successfully describe these mechanisms in III-V high carrier concentration (≥10 ²⁰ ) DMSs and in nearly insulated (≤10 ¹⁷ ) DMOs, respectively.  However, neither model can describe both mechanisms for DMOs with moderate carrier concentrations (10 ¹⁷ ≤n≤.10 ²⁰ ).  In this talk, a delicate experiment was designed to unlock this secret.  The finding infers a simple model that can explain the origin of the magnetic coupling and spin current for DMOs.