Ferromagnetic resonance study of sputtered NiFe/V/NiFe heterostructures

AbstractThe Ni81Fe19/V/Ni81Fe19 heterostructures has been produced by magnetron sputtering and analyzed by ferromagnetic resonance. Two systems were investigated: the non symmetrical NiFe(50Å)/V(t)/NiFe(30Å) trilayers and the symmetrical NiFe(80Å)/V(t)/NiFe(80Å) trilayers, with variable ultrathin V thickness t. Ferromagnetic exchange coupling was evidenced for t below 10Å by the excitation of the optic mode, in the case of the non symmetrical samples, and by the observation of a single resonance mode for the symmetrical trilayers. For larger V thickness, all samples exhibited two modes, which were attributed to the resonance of the individual NiFe layers with different effective magnetizations. The analysis with the equilibrium and resonance conditions provided the exchange coupling constants and effective magnetizations

Nanocrystal formation in silicon oxy-nitride films for photovoltaic applications: Optical and electrical properties

Thin films of nanocrystalline SiOxNy are studied in view of their application in silicon heterojunction (SHJ) solar cells. In particular, the formation of the nanocrystals and their effects on the electrical and optical properties of the films are investigated. The role of the oxygen content on the properties of the layers is clarified as well. The obtained layers show very high conductivity (44 S/cm), low activation energy (1.85 meV) and high Tauc gap (2.5 eV), promising features for their application in photovoltaics