Exchange coupling in FeTaN-FeSm-FeTaN multilayers: a Kerr effect study

The dependence of the interlayer coupling on both the soft (FeTaN) and hard (FeSm) layer thickness in FeTaN-FeSm-FeTaN multilayers, deposited by dc magnetron sputtering, has. been investigated. The magnetization reversal process is examined experimentally using a magnetooptical Kerr effect. The exchange field H_ex, which is a measure of the average coupling between the soft and hard layers, was determined from the field shift of the minor hysteresis loop. The value of H_ex increases as the number of the soft FeTaN layer increases. A significant and fully reversible transverse hysteresis loop was measured indicating that, during the magnetization-reversal process, the magnetic moments in the soft layers rotate reversibly, as typical of exchange-spring systems.