Micromagnetic simulations of submicron vortex structures for the detection of superparamagnetic labels

Author(s)
Lukas Wetterau, Claas Abert, Dieter Suess, Manfred Albrecht, Bernd Witzigmann
Abstract

We present a numerical investigation on the detection of superparamagnetic labels using a giant magnetoresistance (GMR) vortex structure. For this purpose, the Landau–Lifshitz–Gilbert equation was solved numerically applying an external z-field for the activation of the superparamagnetic label. Initially, the free layer’s magnetization change due to the stray field of the label is simulated. The electric response of the GMR sensor is calculated by applying a self-consistent spin-diffusion model to the precomputed magnetization configurations. It is shown that the soft-magnetic free layer reacts on the stray field of the label by shifting the magnetic vortex orthogonally to the shift direction of the label. As a consequence, the electric potential of the GMR sensor changes significantly for label shifts parallel or antiparallel to the pinning of the fixed layer. Depending on the label size and its distance to the sensor, the GMR sensor responds, changing the electric potential from 26.6 mV to 28.3 mV.

Organisation(s)
Physics of Functional Materials
External organisation(s)
Universität Kassel, Universität Augsburg
Journal
Sensors
Volume
20
Pages
1-13
No. of pages
13
ISSN
1424-8220
DOI
https://doi.org/10.3390/s20205819
Publication date
10-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103017 Magnetism
Keywords
ASJC Scopus subject areas
Analytical Chemistry, Biochemistry, Atomic and Molecular Physics, and Optics, Instrumentation, Electrical and Electronic Engineering
Portal url
https://ucris.univie.ac.at/portal/en/publications/micromagnetic-simulations-of-submicron-vortex-structures-for-the-detection-of-superparamagnetic-labels(12b120a5-da87-4acc-bf45-bad160b5bdf5).html