A multidisciplinary approach to study the functional properties of neuron-like cell models constituting a living bio-hybrid system: SH-SY5Y cells adhering to PANI substrate
One of the more challenging aspects in cognitive or in rehabilitation neurosciences is the design of functional hybrid systems able to mimic the brain functionality, to connect and to exchange information between biological materials, like brain or neurons, and man-made electronic devices.
Snell’s law describes the refraction of waves at the transition between two media with different indices of refraction. In optics, the dispersion relation of light is isotropic, and thus, the relation between the incident and refracted angles is solely determined by the ratio of the refractive indices. In contrast, for spin waves in thin films with in-plane magnetization the dispersion relation is inherently anisotropic, and thus, deviations from the Snell’s law in optics are expected but have not been reported directly so far.
N-type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities, routinely used for the n-type doping of GaAs epilayers, is enhanced by the nanowire growth mechanism and growth conditions. Among the various possible donor impurities for GaAs NWs, tellurium represents a good candidate since it is a very effective dopant in GaAs epilayers and does not present any risk of amphoteric behavior.
The search for novel tools to control magnetism at the nanoscale is crucial for the development of new paradigms in optics, electronics and spintronics. To date, the fabrication of magnetic nanostructures has been achieved mainly through irreversible structural or chemical modiﬁcations.
Here, we propose a new approach, based on thermally assisted magnetic scanning probe lithography (tam-SPL), for creating reconﬁgurable magnetic nanopatterns by crafting, at the nanoscale, the magnetic anisotropy landscape of a ferromagnetic layer exchange-coupled to an antiferromagnetic layer. By performing localized ﬁeld cooling with the hot tip of a scanning probe microscope, magnetic structures, with arbitrarily oriented magnetization and tunable unidirectional anisotropy, are reversibly patterned without modifying the ﬁlm chemistry and topography. This opens unforeseen possibilities for the development of novel metamaterials with ﬁnely tuned magnetic properties, such as magnonic crystals allowing active manipulation of spin waves. In this context, we present a proof-of-concept experiment, performed by micro-focused Brillouin light scattering (µ-BLS), showing that local control of the spin wave excitation and propagation can be obtained in reconﬁgurable magnetic tracks patterned with tam-SPL.