DEFECT STUDIES OF THIN LAYERS BY THE VIBRATING-REED TECHNIQUE

The vibrating-reed technique has been successfully adapted to internal friction studies of thin-layer materials. Three examples are described, related to the oxygen contamination of niobium films, grain-boundary sliding of aluminum films, and anelasticity due to hydrogen in metallic glasses. Emphasis is given to the use of thin high-Q substrates as a means of examining supported films down to 0.1µm thickness. It has been found that the behavior of films can be radically different from that of bulk samples. For example, two-stage grain-boundary sliding with an activation energy of only 0.55eV has been observed in aluminum films. In metallic glasses, a peak associated with the presence of hydrogen in small low-symmetry interstitial sites has been found in many different alloys, including Pd80Si20, Fe80B20, Nb40Ni60 and Cu57Zr43

SNOEK AND GORSKY RELAXATIONS IN HYDROGENATED METALLIC GLASSES

Deux relaxations, l'une due à une réorientation atomique à courte distance, l'autre due à un effet Gorsky à longue distance, ont été observées dans du Ni64Zr36 vitreux contenant jusqu'à 20 pour cent d'hydrogène (fraction atomique). Les caractéristiques complémentaires de ces deux relaxations dues à des réorientations montrent qu'elles sont du type Snoek. L'ampleur de la relaxation Gorsky est faible, et ne varie que légèrement en fonction de la température, ce qui indique une répulsion H-H.A short-range reorientation relaxation and a long-range Gorsky relaxation have been observed in glassy Ni64Zr36 containing H up to 0.2 atom fraction. The relaxations exhibit mutually complementary characteristics that establish the reorientation relaxation to be of the Snoek-type. The Gorsky relaxation strength is small, and exhibits a weak temperature dependence indicative of a H-H repulsion