Static and dynamic magnetic properties of circular and square cobalt nanodots in hexagonal cells.

In this work we performed a detailed numerical analysis to investigate the static and dynamic magnetic properties of hexagonal cells of square and circular cobalt nanodots as a function of the distance between them and the external magnetic field to which they are subjected. By simulating hysteresis curves with the external magnetic field applied parallel and perpendicular to the plane of these nanostructures, we can conclude that the cobalt nanodots presented a significant perpendicular magnetic anisotropy. We also obtained that the coercivity increases with decreasing volume, which implies that the circular dots have a higher coercivity than the square dots.

Dynamic susceptibility of FeO nanotubes.

In this work we performed a detailed numerical analysis to investigate the dynamic susceptibility of 1000 nm long FeO nanotubes by varying the diameter, the tube wall thickness and the magnitude of the external magnetic field applied along the tube axis. We found two well-defined modes, one of low frequency associated with the caps of the nanotubes, and another of high frequency associated with the central area of the nanotubes, which can be controlled by varying the geometry of the tubes or the external magnetic field to which they are subjected. These results allow us to suggest the use of these nanotubes in applications that require controlling the resonant frequency in the GHz range.

Permalloy nanowires/graphene oxide composite with enhanced conductive properties.

Carbon-metal-based composites arise as advanced materials in the frontiers with nanotechnology, since the properties inherent to each component are multiplexed into a new material with potential applications. In this work, a novel composite consisting of randomly oriented permalloy nanowires (Py NWs) intercalated among the sheets of multi-layered graphene oxide (GO) was performed. Py NWs were synthesized by electrodeposition inside mesoporous alumina templates, while GO sheets were separated by means of sonication.

Disorder in H-irradiated HOPG: effect of impinging energy and dose on Raman D-band splitting and surface topography.

Disorder was induced in pristine highly oriented pyrolytic graphite (HOPG) by irradiation with H ions with energies of 0.4 MeV and 1 MeV, and doses of 10 ions/cm and 10 ions/cm. Raman spectroscopy was used as the main technique to characterize different samples and gain new insights on the splitting of the D band into two components (D and D), trying to correlate this feature of the vibrational spectrum with the impinging energy and dose.

C58 on Au(111): a scanning tunneling microscopy study.

C58 fullerenes were adsorbed onto room temperature Au(111) surface by low-energy (~6 eV) cluster ion beam deposition under ultrahigh vacuum conditions. The topographic and electronic properties of the deposits were monitored by means of scanning tunnelling microscopy (STM at 4.2 K).