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.
Recent research on hybrid plasmonic systems has shown the existence of a loss channel for energy transfer between
organic materials and plasmonic/metallic structured substrates. This work focuses on the exciton-plasmon coupling
between para-Hexaphenylene (p-6P) organic nanofibers (ONFs) and surface plasmon polaritons
(SPPs) in organic/dielectric/metal systems. We have transferred the organic p-6P nanofibers onto a thin silver film
covered with a dielectric (silicon dioxide) spacer layer with varying thicknesses. Coupling is investigated by two-photon
fluorescence-lifetime imaging microscopy (FLIM) and leakage radiation spectroscopy (LRS). Two-photon excitation
allows us to excite the ONFs with near-infrared light and simultaneously avoids direct SPP excitation on the metal layer.
We observe a strong dependence of fluorescence lifetime on the type of underlying substrate and on the morphology of
the fibers. The experimental findings are complemented via finite-difference time-domain (FDTD) modeling. The
presented results lead to a better understanding and control of hybrid-mode systems, which are crucial elements in future
low-loss energy transfer devices.