Micromagnetic Simulation of Spin Valves with Synthetic Free and Pinned Layers and Detection of Magnetic Labels with AC Field

Author

Liu, Yaowen ; Hou, Zhiwei

Author_Institution

Dept. of Phys., Tongji Univ., Shanghai

Volume

43

Issue

6

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

2932

Lastpage

2934

Abstract

We present a micromagnetic simulation for detection of magnetic labels modulated by an ac magnetic field. As the sensing element, spin valves with synthetic ferrimagnetic (SF) free and pinned layers are optimized. At lower fields, the sensors with SF free layers show linear transfer curves, demonstrating a coherent switching due to the strong antiferromagnetic coupling inside the SF free layers. The sensor offset field can be reduced by tuning the effective thickness of SF free and pinned layers. Magnetic simulation for the detection of 250-nm magnetic labels with this sensor shows a linear giant magnetoresistive signal dependence on the number of particles.

Keywords

biological techniques; biomagnetism; biosensors; cobalt alloys; enhanced magnetoresistance; exchange interactions (electron); ferrimagnetic materials; iron alloys; magnetic sensors; micromagnetics; microsensors; nickel alloys; ruthenium; spin valves; CoFe-NiFe-Ru; ac magnetic field; antiferromagnetic coupling; coherent switching; giant magnetoresistance; linear transfer curves; magnetic label detection; micromagnetic simulation; pinned layers; sensor offset field; spin valves; synthetic ferrimagnetic free layers; Antiferromagnetic materials; Biosensors; Ferrimagnetic materials; Giant magnetoresistance; Magnetic sensors; Magnetic separation; Magnetization; Micromagnetics; Molecular biophysics; Spin valves; Magnetic bead detection; micromagnetic simulation; spin valve; synthetic ferrimagnetic layers;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2007.892320

Filename

4202765