SHEAR MODULUS OF COEVAPORATED NI1-XZRX THIN-FILMS

Electron-beam evaporation was used to deposit Ni1-xZrx alloy thin film s, 0 < x < 1.0, onto piezoelectric quartz-crystal substrates. For 0.1 < x < 0.87, the films are single-phase amorphous. Surface acoustic (Ra yleigh) waves were generated and detected on the substrates using inte rdigital transducers predeposited on the substrate surface. The differ ence between the Rayleigh wave velocity before and after the depositio n of the Ni1-xZrx films is used to deduce the shear modulus, mu(x), of the films through a first-order perturbation theory. For all composit ions, mu(x) is lower than the weighted average of the mu values of the pure Ni and Zr films. Within the range 0.1 < x < 0.87, mu(x) has five narrow maxima indicative of chemical short-range ordering at selected compositions.