Magnetic transport properties of Co90Fe10/AlO x,/Co90Fe10/AlOx/Co 90Fe10 ferromagnetic double tunnel junctions have been investigated with respect to the thermal fluctuation. A middle Co 90Fe10 layer is discontinuous by forming Co 90Fe10 particles two-dimensionally, which shows superparamagnetic behavior above 80 K. The average diameter of the Co 90Fe10 particles is estimated to be 4.8-5.0 nm from both a magnetization curve at room temperature and temperature dependence of coercivities deduced from magnetoresistance curves. This finding agrees with the maximum diameter (5.2 nm) evaluated from cross-sectional transmission electron microscope images, revealing that the dominant electron transport process heavily depends on the largest particles.
- Double tunnel junction
- Tunnel magnetoresistance
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Physics and Astronomy (miscellaneous)