Pinning-assisted out-of-plane anisotropy in reverse stack FeCo/FePt intermetallic bilayers for controlled switching in spintronics

[摘要] We study the implications of FeCo underlayer and overlayer on the static and dynamic magnetic properties of FeCo/FePt exchange spring system along with post-annealing kinetics. Probing of FePt/FeCo/Si and FeCo/ FePt/Si bilayers using high energy synchrotron X-ray diffraction by varying glancing angles unveiled structural variations at the interface, where FeCo is observed to inhibit the crystalline growth of FePt. A soft ferromagnetic in-plane behavior and defect-driven hard ferromagnetic properties in the out-plane con -figuration are established. Besides, the magnetization dynamics studied by Ferromagnetic Resonance de-picts an out-plane magnetization component of FePt only in FeCo/FePt/Si. X-ray Absorption Spectroscopy (XAS) in the Fe, Co and Pt L-edge regions reveal dissimilar interfaces in the two series due to thermal agitation effects. XAS spectra at Fe and Co K-edges ensure similar local coordination of Co immaterial of stack order, contrary to altered local geometry of Fe observed in the two series ascribed to varied crys-tallinity of FePt. Such structures are useful for spin-wave assisted low field magnetization switching in highly coercive FePt by using exchange coupled soft FeCo. (c) 2021 Elsevier B.V. All rights reserved.

[发布日期] 2021-10-05

[关键词] Exchange-spring;Anisotropy;Interface;Pinning;Gilbert damping;Charge transfer