Quelques propriétés magnétiques, électriques et optiques des films obtenus par électrolyse et par évaporation thermique

Abstract
Several experiments were carried out. Composites of thin layers of ferromagnetic materials, deposited by electrolysis, show an increase of the coercive force with decreasing thickness, as predicted by theory. The magnitude of the effect shows that both the cristal anisotropy and shape anisotropy contribute. Thin precipitates of some magnetic materials of high coercive force, studied by methods of measurements of the magnetic torque, are proved to be effective because of their shape anisotropy, magnetic crystal anisotropy being of secondary importance. Thin films of copper and others metals are produced by rapid evaporation (500 to 1000 Å /sec) and found to have a better mechanical structure than those produced slowly with the same residual gas pressure. The mean free path calculated from the resistivity has the expected magnitude. It is shown that a thin layer of the semiconductor GaSb is a photoelectric conductor. The electronic mobility (Hall effect) is of the order of 10-2 of that of the bulk material. Certain techniques are reported for preparing films of zinc 400 thick, on a free layer of cellulose acetate, the thickness of such composites being about 1 000 Å.