MAGNETIC AND STRUCTURAL-PROPERTIES OF CO COO BILAYERS/

The magnetic and structural properties of Co/CoO bilayers prepared by sputtering have been studied in films with Co thickness in the range o f 65 to 250 angstrom. A two-phase structure consisting of hcp Co and f cc CoO was observed in the films. The coercivity was found to change i nversely proportional to the Co thickness and to the sputtering rate. The highest H(c) (9 kOe) was obtained in films exposed to ambient cond itions for long periods of time. A shift in the hysteresis loop was fo und in field-cooled samples, indicating a strong exchange coupling bet ween the Co and CoO phases.