Title

Development of a High Frequency Probe Station Built to Study Spin Valves

Publication Date

10-2002

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Engineering, Electrical Engineering

Department

Electrical and Computer Engineering

Major Advisor

Susan L. Burkett

Abstract

Spin valves are GMR devices that are used in sensing the magnetic orientation of hard drive media. Recent trends show that the size of these devices, used in read heads of hard drives, is getting smaller at a rapid rate. To measure the resistance of these devices a calibrated bias current must be applied to them and a resulting voltage can then be measured. The voltage would then change and could be sensed according to the resistance change of the device caused by the application of a magnetic field to the spin valve. The bias current applied must be large enough to achieve an acceptable signal to noise ratio (SNR). The decreasing size of these devices implies the current density applied will continue to increase.

This illustrates the importance of studying the effects of high current density on the magnetoresistance characteristics of these devices. This thesis covers steps taken to build an experimental test setup to look at these effects. A method that involves applying short duration (~ns) high current density pulses to the devices. It was confirmed from previous work that this method does not damage the devices and that this could enable study of the effects of high current density affects without heating the devices to the point of degrading the magnetic properties. The actual experiment of studying these effects utilizing this experimental test setup is suggested for future work.

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