Improvements of sensing performance by specially designed magnetic shield layer in an in vitro tunneling magnetoresistance biosensor using immobilized ferrimagnetic nanoparticle agents

Abstract

The dependence of magnetic shield layer thickness, permeability of the shield materials, and shielding gap width on the sensing performance of an in vitro exchange biased tunneling magnetoresistance (TMR) spin-valve biosensor with immobilized ferrimagnetic sensor agents has been numerically analyzed by using a finite element method. It was numerically demonstrated that the specially designed magnetic shield layer on the surface of the TMR biosensors is considerably effective to improve the switching field uniformity and to eliminate an undesirable undershoot magnetic field formed on the sensor surface. © 2008 American Institute of Physics.