Title :
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
fDate :
6/1/2007 12:00:00 AM
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;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2007.892320
