Low-current spin transfer torque MRAM
Guohan Hu, J. J. Nowak, et al.
VLSI-TSA 2017
We report on the fabrication of nanoscale, three-terminal in-plane spin-orbit torque switching devices with low switching current densities. Critical parameters in the fabrication process, including the ion beam etching angle and time, were optimized to avoid fabrication defects and improve device yield. Measurements of the magnetic field and current-induced switching behavior of the tunnel junctions demonstrate a sensitivity to the nanopillar aspect ratio, which dictates the nanopillars’ anisotropy and thermal stability. Additionally, we show that the current density required for switching can be reduced and the device thermal stability increased by inserting Hf interlayers into the heterostructure. Micromagnetic simulations are generally consistent with the experimentally observed switching behavior, suggesting an increase in the interfacial perpendicular anisotropy at the CoFeB/MgO interface and the reduction in the Dzyaloshinskii-Moriya interaction at the W/CoFeB interface by the Hf interlayers.
Guohan Hu, J. J. Nowak, et al.
VLSI-TSA 2017
Jonathan Z. Sun
Physical Review B
Jonathan Z. Sun
Physical Review B
Jonathan Z. Sun, Christopher Safranski
J Magn Magn Mater