Analysing a magnetic molecule detection system--computer simulation.
The detection of single molecules, e.g. in biology is possible by marking the interesting molecules with magnetic beads and detect the influence of the beads on giant magnetoresistance (GMR)/tunnel magnetoresistance (TMR)/spin valve (SV) sensors. The development of suitable multilayers has been studied experimentally as well as theoretically in order to optimize the sensor parameters. A finite difference (FD) method including the usually used contributions to the total energy [exchange, antiferromagnetically (af) coupling, anisotropy and magnetostatic] is used for the simulation with additional contributions to the local field according to the stray fields of the beads. In this work, we will show the results of micromagnetic calculations of the magnetization behavior of GMR/TMR sensors considering also the interaction between the domains in the magnetic layers of the sensor and the bead area. We can present first calculations where the bead particles (signal source) and the magnetic layers (sensor device) are considered as a whole magnetic ensemble.
Schepper
W
W
Department of Physics, University of Bielefeld, Universitätsstrasse 25, 33501 Bielefeld, Germany. schepper@physik.uni-bielefeld.de
Schotter
J
J
Brückl
H
H
Reiss
G
G
D001704:Biopolymers / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D004574:Electromagnetic Fields; D019544:Equipment Failure Analysis / Q000379:methods; D018189:Immunomagnetic Separation / Q000295:instrumentation / Q000379:methods; D008280:Magnetics / Q000295:instrumentation*; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D008846:Micromanipulation / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D008956:Models, Chemical; D008967:Molecular Biology / Q000295:instrumentation / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers
D001704:Biopolymers