Present paper deals with the planar Hall effect (PHE) of Ta(5 nm)/NiFe(t_f)/Cu(1.2 nm)/NiFe(t_p)/IrMn(15 nm)/Ta(5 nm) spin-valve structures. Experimental investigations are performed for 50 × 50 μm² junctions with various thicknesses of free and pinned layer t_f 4, 8, 10, 15, 20 nm and t_p 2, 3, 6, 8, 9, 12 nm. The results show that the thicker free layers, the higher PHE signal is obtained. In addition, the thicker pinned layers, the lower PHE signal. The highest PHE sensitivity S of 15.6 mΩ/Oe is obtained in the spin-valve configuration with t_f 20 nm and t_p 2 nm. This optimum structure is rather promising for micro magnetic bead detections. © 2009 IOP Publishing Ltd.

Tu B.D., Cuong L.V., Huong Giang D.T., Danh T.M., Duc N.H.

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