We demonstrate the reduction of critical spin-transfer torque (STT) switching currents in Co-Fe-B/MgO based magnetic tunnel junctions (MTJ) with perpendicular magnetization anisotropy (PMA). The junctions yield tunnel magnetoresistance (TMR) ratios of up to 64% at 4 monolayer (ML) tunnel barrier thickness. In this paper, the reduction of the critical switching current density is studied. By optimizing the applied bias field during DC-STT measurements, ultra low critical switching current densities of less than 20 kA/cm2, even down to 9 kA/cm2, are found. With the reduced switching currents, our samples are ideal candidates for further experimental studies such as the theoretical predicted thermally driven spin-transfer torque effect.
@article{arxiv.1309.3397,
title = {Spin-transfer torque switching below 20 kA/cm$^2$ in perpendicular magnetic tunnel junctions},
author = {Johannes Christian Leutenantsmeyer and Marvin Walter and Steffen Wittrock and Patrick Peretzki and Henning Schuhmann and Michael Seibt and Markus Münzenberg},
journal= {arXiv preprint arXiv:1309.3397},
year = {2013}
}