Observation of the Temperature driven Insulator to Semiconductor (Ferromagnetic) Phase

We investigated the changes of magnetic properties (para to ferromagnetic) and phase transitions (insulator to semiconductor) in films of EuO grown on a MgO(100) single crystal as a function of temperature. In between 70 K, we found a clear phase transition and magnetic transition using the spin-summed and spin-resolved photoemission spectra, as well as the low energy electron diffraction. We will elucidate the temperature driven electronic and magnetic property in EuO on MgO(100) substrate.