RESUMO
Gamma photons with an average energy of 1.25 MeV are well-known to generate large amounts of defects in semiconductor electronic devices. Here we investigate the novel effect of gamma radiation on diffusive memristors based on metallic silver nanoparticles dispersed in a dielectric matrix of silica. Our experimental findings show that after exposure to radiation, the memristors and artificial neurons made of them demonstrate much better performance in terms of stable volatile resistive switching and higher spiking frequencies, respectively, compared to the pristine samples. At the same time we observe partial oxidation of silver and reduction of silicon within the switching silica layer. We propose nanoinclusions of reduced silicon distributed across the silica layer to be the backbone for metallic nanoparticles to form conductive filaments, as supported by our theoretical simulations of radiation-induced changes in the diffusion process. Our findings propose a new opportunity to engineer the required characteristics of diffusive memristors in order to emulate biological neurons and develop bio-inspired computational technology.
RESUMO
The full, ordered, antiferromagnetic Heusler alloy Pd(2)MnIn has been investigated using synchrotron radiation photoelectron spectroscopy. The Pd 4d Cooper minimum at 130 eV photon energy and the Mn 3p to 3d resonance at 49.5 eV photon energy have been used to determine the partial spectral weights of the Pd 4d and Mn 3d derived states. These partial spectral weights are consistent with published partial density of states calculated using the augmented spherical wave method. A quantitative fit of the resonant profile yielded an asymmetry parameter of 1.6 ± 0.4, indicating delocalization of the filled Mn 3d states.
