Iron‐iron oxide layer films

Thin alternating layers of bcc Fe/amorphous Fe oxide were prepared by a new pulse reactive sputtering technique. The thickness of the Fe+(Fe oxide) periods varied from 8 to 540 A. At room temperature, the films have soft magnetic properties with coercivities of 4–10 Oe. Samples cooled to 5 K in a saturating applied field show large coercive fields, displaced hysteresis loops and thermal irreversibility up to about 100 K. This low temperature behavior is evidence of exchange coupling between the ferromagnetic Fe and the amorphous Fe oxide.