11:00 AM, Feb 24, 2011
Sumwalt, Room 102

Bochen Zhong
"Low frequency noise characteristics of sub-micron magnetic tunnel junctions".

Abstract : We report that low frequency (up to 200 kHz) noise spectra
of magnetic tunnel junctions with areas 10^(-10) cm^2 at 10 Kelvin
deviate signicantly from the typical 1/f behavior found in large area
junctions. In most cases, a Lorentzian-like shape with characteristic
time between 0.1 and 10 ms is observed, which indicates only a small
number of fluctuators contribute to the measured noise. By
investigating the dependence of noise on both the magnitude and
orientation of an applied magnetic field, we find that magnetization
fluctuations in both free and reference layers are the main sources
of noise in these devices. At small fields, where the noise from the
free layer is dominant, a linear relation between the measured noise
and angular magnetoresistance susceptibility can be established.