Tuesday, September 25, 2012

1209.5226 (Aymen Ben Hamida et al.)

Impact of current paths on measurement of tunneling magnetoresistance
and spin torque critical current densities in GaMnAs-based magnetic tunnel
junctions
   [PDF]

Aymen Ben Hamida, Florian Bergmann, Klaus Pierz, Hans Werner Schumacher
GaMnAs-based magnetic tunnel junction (MTJ) devices are characterized by in-plane and perpendicular-toplane magnetotransport at low temperatures. Perpendicular-to-plane transport reveals the typical tunneling magnetotransport (TMR) signal. Interestingly, a similar TMR signature is observed in the in-plane transport signal. Here, low-ohmic shunting of the MTJ by the top contact results in significant perpendicular-to-plane current paths. This effect allows the determination of TMR ratios of MTJs based on a simplified in-plane measurement. However, the same effect can lead to an inaccurate determination of resistance area products and spin torque critical current densities from perpendicular-to-plane magnetotransport experiments on MTJ pillar structures.
View original: http://arxiv.org/abs/1209.5226

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