Hysteresis-free magnetization reversal of exchange-coupled bilayers with finite magnetic anisotropy

Author(s)
Christoph Vogler, Michael Heigl, Andrada-Oana Mandru, Birgit Hebler, Miguel Marioni, Hans Josef Hug, Manfred Albrecht, Dieter Suess
Abstract

Exchange-coupled structures consisting of ferromagnetic and ferrimagnetic layers become technologically more and more important. We show experimentally the occurrence of completely reversible, hysteresis-free minor loops of [Co (0.2 nm)/Ni(0.4 nm)/Pt(0.6 nm)](N) multilayers exchange-coupled to a 20-nm-thick ferrimagnetic Tb28Co14Fe58 layer, acting as a hard magnetic pinning layer. Furthermore, we present detailed theoretical investigations by means of micromagnetic simulations and, most importantly, a purely analytical derivation for the condition of the occurrence of full reversibility in magnetization reversal. Hysteresis-free loops always occur if a domain wall is formed during the reversal of the ferromagnetic layer and generates an intrinsic hard-axis bias field that overcomes the magnetic anisotropy field of the ferromagnetic layer. The derived condition further reveals that the magnetic anisotropy and the bulk exchange of both layers, as well as the exchange coupling strength and the thickness of the ferromagnetic layer, play an important role for its reversibility.

Organisation(s)
Physics of Functional Materials
External organisation(s)
Universität Augsburg, Eidgenössische Materialprüfungs- und Forschungsanstalt, Universität Basel, Christian Doppler Laboratory for Advanced Magnetic Sensing and Materials
Journal
Physical Review B
Volume
102
No. of pages
9
ISSN
2469-9950
DOI
https://doi.org/10.1103/PhysRevB.102.014429
Publication date
07-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
103015 Condensed matter, 103018 Materials physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/hysteresisfree-magnetization-reversal-of-exchangecoupled-bilayers-with-finite-magnetic-anisotropy(ee218eb8-9911-4dbd-be66-d7f8bc3fc83e).html