A new type of perpendicularly magnetized memory is explored, combining the spin Hall effect as a switching mechanism with the electric field effect as a selector. Calculations predict that this method is feasible. Magnetization reversal experiments show a coercivity modification between 4.5 mT and 13 mT for voltages between -2 V and +2 V. Two sensitivity regions are identified: a low sensitivity region of 0.5 mT/V for -0.8 V < V < 1.6 V and a high sensitivity region of 4.5 mT/V for higher voltages up to ±2.0 V. A logarithmic time dependence of the coercivity is found for voltages in the higher sensitivity region, which is attributed to a changing stoichiometry of the AlOx-Co interface due to migrating oxygen vacancies. The logarithmic time dependence is explained using a thermal fluctuation aftereffect model. Experimental results on spin Hall torque switching of a PMA microwire are in good agreement with the literature, showing that similar devices could be used in future projects.
|Date of Award||30 Jun 2014|
|Supervisor||Henk J.M. Swagten (Supervisor 1) & A. van den Brink (Supervisor 2)|