EuO films doped with Fe and Gd

EuO films doped with Fe and Gd+++ raise the Curie temperature to ≳200°K (from 70°K for EuO). The magnetic moment is slightly reduced to 200 emu/g (vs 232 emu/g for EuO). The characteristic optical absorption band, which is due to an electronic transition from 4f to 5d levels of Eu++ ions, remains unchanged with the peak absorption of 2.4×105/cm at 5800 Å. The longitudinal Faraday rotation at 6328 Å with an incident angle of 65°is 1.9×105 and 1.4×105 deg/cm at 7.0 and 77°K, respectively. Films deposited on several types of glasses possess square hysteresis loops with higher values of Hc (86 ∼ 100 Oe at T<10°K and less than 53 Oe at T=77°K), both of which are essential for device applications. © 1972 The American Institute of Physics.