Epitaxial La 2 NiMnO 6 thin films have been grown on (001)-orientated SrTiO 3 using the pulsed laser deposition technique. The thin films samples are semiconducting and ferromagnetic with a Curie temperature close to 270 K, a coercive field of 920 Oe, and a saturation magnetization of 5 µ B per formula unit. Transmission electron microscopy, conducted at room temperature, reveals a majority phase having "I-centered" structure with a ≈ c ≈ a sub 2 and b ≈ 2a sub along with minority phase domains having a "P-type" structure (a sub being the lattice parameter of the cubic perovskite structure). A discussion on the absence of Ni/Mn long-range ordering, in light of recent literature on the ordered double-perovskite La 2 NiMnO 6 is presented.

High quality vanadium sesquioxide V2O3 films (170–1100Å) were grown using the pulsed laser deposition technique on (0001)-oriented sapphire substrates, and the effects of film thickness on the lattice strain and electronic properties were examined. X-ray diffraction indicates that there is an in-plane compressive lattice parameter (a), close to −3.5% with respect to the substrate and an out-of-plane tensile lattice parameter (c). The thin film samples display metallic character between 2 and 300K, and no metal-to-insulator transition is observed. At low temperature, the V2O3 films behave as a strongly correlated metal, and the resistivity (ρ) follows the equation ρ=ρ0+AT2, where A is the transport coefficient in a Fermi liquid. Typical values of A have been calculated to be 0.14μΩcmK−2, which is in agreement with the coefficient reported for V2O3 single crystals under high pressure. Moreover, a strong temperature dependence of the Hall resistance confirms the electronic correlations of these V2O3 thin film samples.

International audienceAlN, GaN, and InN were irradiated at room temperature with monatomic swift heavy ions and high-energy fullerenes. Ion track formation was studied using transmission electron microscopy in both plane view and cross-sectional modes. A full experimental description of ion track formation in these compounds is presented. AlN shows a remarkable resistance towards track formation; InN is the most sensitive and shows partial decomposition, likely into N-2 and metallic clusters; the overlapping of the amorphous tracks in GaN does not give an amorphous layer because of a track-induced recrystallization. We discuss the application of the inelastic thermal spike model, which allows good and simple predictions of track radii in oxides, to the studied III-nitrides, and in general to semiconductors