Spin-transfer induced switching in nanomagnetoresistive devices composed of Co/Pt multilayers with perpendicular magnetic anisotropy

Abstract

We demonstrate spin-transfer switching of nanomagnetic devices composed of Co/Pt multilayer electrodes with perpendicular magnetic anisotropy. In order to obtain highly spin-polarized current, we have proposed the adoption of thick Co adjacent layers. The film stack has been optimized so that two different Co/Pt multilayer electrodes switch separately, with each having narrow switching field distribution. Detrimental effects of surface roughness have been observed and minimized to achieve well-defined switching behavior. Diverse nanopillar devices fabricated by e-beam lithography and subsequent processes show well-defined single step switching in both perpendicular field and injected current applications. The critical current density obtained is comparable to that of Co/Ni electrode based devices, indicating enhanced spin-transfer efficiency.

Tailoring magnetic vortices in nanostructures

“…Moreover, these systems have been shown to present TMR or GMR. 9,[13][14][15] In this letter, we propose Co/Pt multilayer engi-neering to tailor the Co vortex properties by means of the interface contribution to K eff ; we show how the vortex core magnetization and radius ͑r͒ can be tailored by controlling K eff .…”

Temperature dependent coercivity crossover in pseudo-spin-valve magnetic tunnel junctions with perpendicular anisotropy

“…[5][6][7][8][9] Lots of studies have been carried out on the fabrication and characterization of pMTJs with AlO x and MgO barriers. [10][11][12][13][14] Promising progress has been made not only on reaching high tunneling magnetoresistance (TMR) ratios but also achieving a low critical current density. [15][16][17] Here, we report a temperature dependent effect: coercivity crossover.…”