Enhancement of magnetic anisotropy of hydrogenated Pd/Co/Pd trilayers

Abstract

Magnetic and structural properties of Pd/Co/Pd trilayers in hydrogen atmosphere (pressure P H) have been investigated. The Pd layers are well hydrogenated and fully transformed to β-Pd–H phase at P H=1 atm, but this β phase is distorted along the film normal under the restriction of substrate, and the atomic ratio of H/Pd is estimated to be 0.6. Hydrogenation at low P H gives rise to enhancement of perpendicular magnetic anisotropy K eff. For instance, 3 Å-thick Co at P H=1.3 atm exhibits very high K eff (3.5×10 7 erg/cm 3) being two times larger than that of as-prepared one (1.6×10 7 erg/cm 3). Further increase in P H decreases K eff gradually, while K eff recovers to some extent after full dehydrogenation.