Preparation and Magnetic Properties of EuO Thin Films Epitaxially Grown on MgO and SrTiO 3 Substrates

Ferromagnetic EuO films were epitaxially grown on MgO and SrTiO 3 substrates aligned with EuO[100]//MgO[100], EuO(001)//MgO(001) and EuO[100]//SrTiO 3 [110], EuO(001)//SrTiO 3 (001). The single phase EuO film was obtained on MgO substrate. The higher order oxides, Eu 2 O 3 , was always present in the films on SrTiO 3 substrate due to the reaction of europium metal and grown EuO with oxygen in SrTiO 3 . The optimized flux ratio of oxygen to europium, J OXY / J Eu , was 0.39, for J Eu =2.83× 10 13 cm -2 · s -1 . The representative growth rate was 9.0×10 -2 Å/s on MgO. Magnetic moment per europium atom was 6.9± 0.3 µ B . The Curie temperature was 69 K for films on MgO. The T C higher than 69 K was observed for films on SrTiO 3 thicker than 50 Å. The thickness of 400 Å was enough for the coercive field to be as low as 50 Oe.