Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Final Activity Report Summary - TUNEFIELD (First principles studies of the field-inducedtunability of dielectric properties)

Spintronic, or 'spin-electronic', is an emerging multidisciplinary field whose objective is the exploitation and manipulation of the intrinsic spin of electrons in solid-state devices. Two of the fundamental problems that need to be addressed in this field are the generation of a 'spin signal' and the lifetime of this signal in the device. Different approaches of spin generation exist, either by optical orientation of the spins or by direct injection from a ferromagnetic material.

During this fellowship we proved spin-injection from a fully polarised manganese oxide (La0.7Sr0.3MnO3, or LSMO) into a Carbon nanotube (CNT). By performing first principles' simulations of the contact of the CNT with the LSMO, it was shown that the conducting electrons on the oxide were fully spin polarised, with only electrons with one well defined spin being conductive, and that an energy barrier existed between LSMO and CNT, two ingredients needed to understand the experimental observations.

Once the spin was injected into a conductor, the spin information should be transmitted. However, during this transport of the spin information, a different scattering mechanism could flip the orientation of the spin. In metals, it was the scattering by lattice vibrations (phonons) that dominated. We worked on the implementation of new computational codes to calculate the coupling between electrons and phonons that gave rise to this relaxation of the spin information, using first principles. This would allow for the prediction of spin lifetime in nanodevices for spintronic applications.

Reported by

Capus Universitari, 08193 Cerdanyola del Vallès