The stability of EuO films doped with iron and europium

The feasibility of a low-temperature beam-addressable memory utilizing EuO films doped with iron and excess europium as the storage medium is dependent upon the chemical stability of the divalent state of europium. The stability of such EuO films covered with a protective layer of Eu
2
O
3
has been examined as a function of temperature in various oxidizing atmospheres. The degradation of the films was monitored by measuring optical absorption and transmission, Faraday rotation, coercive force, hysteresis loop squareness, Curie temperature, and lattice constant as the films were progressively aged. The results show that these protected EuO films are stable even in oxidizing atmospheres and at high temperatures relative to the operating temperatures which would be required for a beam-addressable file based on this material.