Thermal magnetic noise and spectra in spin valve heads

In this article we present a quantitative micromagnetic modeling analysis of thermally activated magnetic noise in spin valves heads at deep submicron track widths. It is found that, for these spin valve heads, the thermal magnetic noise is at a magnitude that is comparable to that of the head's Johnson noise. Reducing the sensor track width by keeping the same aspect ratio and film layer thickness will not necessarily yield an increase of thermal magnetic noise, which is attributed to the accompanying increase of the demagnetization field within the sensing layer. However, both the magnitude of noise and the noise spectra are strong functions of the sensor stripe height. An excessive stripe height will yield significantly higher thermal magnetic noise. (C) 2002 American Institute of Physics.