Detection of Magnetic Microbeads Based on NiFeCo/Cu Multilayers Giant Magnetoresistance

Detection of Magnetic Microbeads Based on NiFeCo/Cu Multilayers Giant Magnetoresistance
　　Combined with magnetic labeling, Giant Magnetoresistance (GMR) sensors can be used in biosensors. For applications in diagnosis by detecting the areal density of magnetic microbeads, NiFeCo/Cu multilayers were studied. Firstly, GMR effect was introduced, including the definition of GMR, its theory explanation and model, and several GMR structures. NiFeCo/Cu multilayers were prepared by magnetron sputtering. Dependences of GMR on buffer layer thickness,Neodymium Magnets nonmagnetic layer thickness, and magnetic layer thickness were studied. NiFeCo/Cu multilayers with low saturation field and small hysteresis were obtained. Principles of GMR sensor were analyzed. Dipole field of single magnetic bead and its signal were calculated. GMR sensors http://www.everbeenmagnet.com/ were fabricated by photolithography, sputtering, RIE etc. Tests were done. In conclusion the NiFeCo/Cu multilayers can be used in biosensors and the GMR sensors can detect magnetic microbeads. 更多还原