Integration of Tb/Co multilayers within optically switchable perpendicular magnetic tunnel junctions

This work reports the development of perpendicular magnetic tunnel junctions, based on a multilayered stack of [Tb/Co] nanolayers, in which the magnetization can be reliably toggled using a single optical pulse. The helicity-independent single-shot switching of the magnetization in the Tb/Co multilayered stack was achieved using either 60 fs-long or 5 ps laser pulses with incident fluences down to 4.7 mJ/cm(2). The magnetic switching was achieved for a Co-rich composition window of the multilayer corresponding to layer thickness ratios t(Co)/t(Tb) between 1.3-1.5. This was confirmed for the multilayer alone as well as for the multilayer coupled to aCoFeB electrode, with a structure consisting of CoFeB/Ta/[Tb/Co](N). The optical switching is preserved even after annealing at 250 degrees C in magnetic tunnel junctions (MTJ) electrodes, exhibiting a tunnel magnetoresistance (TMR) of 41% and RxA value of 150 omega mu m after its integration, measured on unpatterned MTJ stacks. These results represent the first step towards the development of hybrid spintronic photonic systems with fJ switching energies.