The electronic structure and the phases of BaVS3

BaVS3 is a moderately correlated d-electron system with a rich phase diagram. To construct the corresponding minimal electronic model, one has to decide which d-states are occupied, and to which extent. The ARPES experiment presented here shows that the behavior of BaVS3 is governed by the coexistence of wide-band (A_1g) and narrow-band (twofold degenerate E) d-electrons. We sketch a lattice fermion model which may serve as a minimal model of BaVS3. This serves foremost for the understanding of the metal-insulator in pure BaVS3 and its absence in some related compounds. The nature of the low temperature magnetic order differs for several systems which may be described in terms of the same electron model. We describe several recent experiments which give information about magnetic order at high pressures. In particular, we discuss field-induced insulator-to-metal transition at slightly subcritical pressures, and an evidence for magnetic order in the high-pressure metallic phase. The phase diagram of Sr-doped BaVS3 is also discussed. The complexity of the phases of BaVS3 arises from the fact that it is simultaneously unstable against several kinds of instabilities.Comment: Presented at the International Conference on Magnetism 2006 (Kyoto), 6 pages, 9 figure

Fullerenelike arrangements in carbon nitride thin films grown by direct ion beam sputtering

Carbon nitride (CNx) thin films were grown by direct N-2/Ar ion beam sputtering of a graphite target at moderate substrate temperatures (300-750 K). The resulting microstructure of the films was studied by high-resolution transmission electron microscopy. The images showed the presence of curved basal planes in fullerenelike arrangements. The achievement and evolution of these microstructural features are discussed in terms of nitrogen incorporation, film-forming flux, and ion bombardment effects, thus adding to the understanding of the formation mechanisms of curved graphitic structures in CNx materials. (C) 2005 American Institute of Physics

Electron microscopy study on the influence of B-implantation on Ni induced lateral crystallization in amorphous Si

Nickel Metal Induced Lateral Crystallization (Ni-MILC) emerged as a viable technique for crystallization of a-Si films decreasing the crystallization temperature. Boron (B) implantation on a-Si films significantly enhances the crystallization rate of the Ni-MILC process. The structural characteristics of the implanted by Boron and subsequently crystallized by MILC a-Si films are studied by Transmission Electron Microscopy (TEM) and they are compared to intrinsic a-Si films which were deposited on top, as well as beside the boron implanted a-Si film. During the annealing, spontaneous nucleation occurs in the B-doped films far from the a-c interface, revealing a shorter incubation period in the B-doped films

INTERACTION OF DISLOCATIONS AND GRAIN BOUNDARIES IN Al FILMS

Les joints de grains des couches minces d'aluminium déposées sous vide sont facettés. Ils contient bien des dislocations. Les dislocations sont produites par les tensions thermiques. Elles passent d'un grain à l'autre. Les irrégularités de surface auprès des joints de grains produisent la formation de segments de dislocations au-dessous des collines sur les couches d'aluminium.The grain boundaries of vacuum deposited Al films are faceted and contain many dislocations. The dislocations originate from thermal stresses mostly and move from boundary to boundary. Surface irregularities at grain boundaries resulted in the formation of dislocation segments under the hills on Al films