All-optical switching in FeCoB/Ta/[Tb/Co]N electrodes for the development of ultrafast magnetic tunnel junctions

LI, G.; RUBIO-ROY, M.; BUDA-PREJBEANU, L. D.; PREJBEANU, I. L.; LUIS AVILES FELIX; DAVIES, C. S.; AUFFRET, S.; SOUSA, R. C.; OLIVIER, A.; ÁLVARO-GÓMEZ, L.; RASING, TH.; DIENY, B.

Conferencia; AIM2021 IEEE Advances in Magnetics 2020-21; 2021

IEEE Magnetics Society

This work reports the development of all-optical switching electrodes consisting of a FeCoB/Ta/[Tb/Co]N for its integration into a magnetic tunnel junction. We explore themagneto-optical properties of [Tb/Co]N multilayers and its thermal stability upon differentannealing temperatures. All-optical helicity independent - switching of the [Tb/Co]multilayers was observed in samples as-grown and even after annealing at 250 °C. In order tofabricate optically switchable electrodes, [Tb/Co] multilayers were coupled to a FeCoB layerthrough a Ta ultra-thin layer. Reversal of the magnetization using ultrafast single laser pulseswas kept after the addition of the FeCoB layers using 60 fs- and 5 ps-long laser pulses withfluences down to 4.7 mJ/cm². Our all-optical switching electrodes FeCoB/Ta/[Tb/Co]N werefinally integrated into a perpendicularly magnetized tunnel junction. Electrical evaluation ofnanopatterned AOS-MTJ showed TMR ratios up to 40 % depending on the diameter of thejunctions and on the number of repetitions of the [Tb/Co] bilayers. Our results can contributeto important advances in ultrafast magnetic random access memories with newfunctionalities, particularly the ability to control the magnetization of the storage layer withultrafast laser pulses.