Increase of curie temperature in euo films by Fe doping

A large increase of ferromagnetic Curie temperature from 69.5 to ∼180°K has been discovered in EuO films by Fe doping. In films containing Fe up to 8% by weight, the structure is essentially the same as bulk EuO, the magnetic moment (at 4.2°K) is reduced slightly to 190 emu/g, the longitudinal Faraday rotation shows a similar wavelength dependence as that of pure EuO with a maximum positive rotation of 2.4×105 deg/cm at 6500 Å at an incidence angle of 65°, square hysteresis loops extend to ∼160°K, and the optical absorption characteristics are modified by Fedoping with a peak absorption coefficient of 2.4×105/cm (at 300°K) at 5800 Å. © 1970 The American Institute of Physics.