Spin-canting effects in GMR sensors with wide dynamic field range

Author(s)
Clemens Muehlenhoff, Christoph Vogler, Wolfgang Raberg, Dieter Suess, Manfred Albrecht
Abstract

Magnetoresistive (xMR) sensors find extensive application in science and industry, replacing Hall sensors in various low field environments. While there have been some efforts in increasing the dynamic field range of xMR sensors, Hall sensors remain to dominate high field applications due to their wide linear range. Using a perpendicularly magnetized reference system and an in-plane free layer allows us to overcome this disadvantage of xMR sensors, and, furthermore, investigate spin-canting effects in interlayer exchange coupled perpendicular synthetic antiferromagnets (p-SAF). We created p-SAFs with exchange coupling fields of up to 10 kOe, based on magnetic Co/Pt multilayer systems. The p-SAFs are either designed as “single” p-SAFs, where two Co/Pt multilayers are interlayer exchange coupled via a 4Å thick Ru spacer, or as “double” p-SAFs, where an additional Co layer is interlayer exchange coupled to the top multilayer. These p-SAFs are used for giant magnetoresistance (GMR) sensors with wide dynamic field range, limited only by the p-SAF’s switching fields. Additionally, the magnetic anisotropy of the in-plane free layer is fully controlled, which allows saturation fields by design. With this, the entire spectrum from parallel to antiparallel alignment of free and reference layer is exploited, which yields the full GMR signal potential. We can show through micromagnetic simulations that certain GMR transfer curves are dominated by spin-canting effects in the interlayer exchange coupled reference system. Finally, our simulation results lay out the correlation of the p-SAF’s design parameters and its magnetization reversal behavior.

Organisation(s)
Physics of Functional Materials, Research Platform MMM Mathematics-Magnetism-Materials
External organisation(s)
Universität Augsburg, Infineon Technologies AG
Journal
IEEE Sensors Journal
Volume
21
Pages
13176-13183
No. of pages
8
ISSN
1530-437X
DOI
https://doi.org/10.1109/JSEN.2021.3067630
Publication date
06-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
103017 Magnetism
Keywords
ASJC Scopus subject areas
Instrumentation, Electrical and Electronic Engineering
Portal url
https://ucris.univie.ac.at/portal/en/publications/spincanting-effects-in-gmr-sensors-with-wide-dynamic-field-range(114fad4c-d072-43fe-a7b3-cfde9b36502b).html