Integration platform for optical switching of magnetic elements

BECKER, H.; KRÜCKEL, C.J.; SOUSA, R.C.; VAN THOURHOUT, D.; HECK, M.J.R.; PELLOUX-PRAYER, J.; DAVIES, C.S.; OLIVIER, A.; KIRILIOUK, A.I.; MORADI, F.; SOBOLEWSKA, E.K.; LI, G.; AVILÉS FÉLIX, L.; PREJBEANU, I.L.; RASING, T.

SPIE

SPIE

Año: 2020 vol. 1146

0277-786X

We present a detailed investigation of a novel platform for integration of spintronic memory elements and a photonic network, for future ultrafast and energy-efficient memory. We designed and fabricated magnetic tunnel junction (MTJ) structures based on (Tb/Co)x5 multilayer stack with optically switchable magnetization. Optical single-pulse measurements allowed us to estimate the value of the stray field present in the parallel configuration, which prevents the structure from all-optical switching. We performed numerical calculations based on the Finite Difference Time Domain method and ellipsometry measurements of (Tb/Co)x5 to compute the absorption by the MTJ structure. Simulation results are in good agreement with the experimental measurements, where we implemented a thermal model to estimate effective absorption in the pillar. These estimations showed up to 14% absorption of the incident optical power in 300-nm-wide MTJ. Moreover, we designed and realized an integrated optical network with focusing structures to efficiently guide and couple the light into the MTJs. We show a chain of necessary steps to obtain the threshold value of the switching energy, and our results presenting a path forward for full system integration of optically switchable MRAM technology