Critical current distribution in spin transfer switched magnetic tunneling junctions

In this paper, the switching current distribution data within a cell is presented. Current switching in the magnetic tunneling junctions (MTJ) is measured in DC pulse mode with pulse widths between 3 ms to 1 s for 25 times or more for each cell. RA of the films is in 10 to 20 Ω-μm² range and TMR values between 18 to 30% are obtained using alumina barrier. It is seen, both from the distribution data as well as by evaluating the analytical expression derived for critical current distribution, that the thermal factor is the most important parameter determining the current distribution within a cell.