Abstract

The ferromagnetic semiconductor EuO, with Curie temperature Tc = 69 K has long been considered a model system since the magnetic moment is highly localized and the exchange interactions are well approximated by the Heisenberg model. Renewed interest has developed because of the possibility of using it in thin-film form as a spin-filter in contact with Si, Ge, or GaAs. Spin injection from EuO into Si has been demonstrated with an extremely high polarization (above 90 %). Despite these highly desirable properties, the low Curie temperature of EuO currently keeps it from technological development in spintronics applications.

In this talk I will discuss how the magnetic moment and Tc change with the film thickness. I will also explore the physics underlying the Tc enhancement of oxygen deficient EuO and La-doped EuO showing some insights from muon spin rotation and relaxation measurements.