Accession Number : AD0615065

Title :   STUDY OF THE BORDONI PEAK IN SINGLE-CRYSTAL AND POLYCRYSTALLINE COPPER,

Corporate Author : UPPSALA UNIV (SWEDEN)

Personal Author(s) : Mongy,M. ; Salama,K. ; Beckman,O.

Report Date : 03 JUL 1964

Pagination or Media Count : 9

Abstract : The Bordoni peak has been investigated in singlecrystal and polycrystalline copper by measuring the longitudinal ultrasonic absorption at 10, 20 and 50 MHz, in the temperature range 80 to 300K. In the single-crystal sample, the measurements have been made in the three principal directions (111), (100) and (110). The values of the activation energy W and the relaxation frequency f sub 0, calculated from the frequency-dependence of the peak on the temperature scale, show a high degree of anisotropy. The comparison of the shape of the peak with Zener's single relaxation theory shows that the peak in the (111) direction is due to a single relaxation process. In the polycrystalline sample and in the other two directions of the single-crystal specimen, the results favour a spectrum of different relaxation frequencies with a constant activation energy. The spectrum width factor gamma differs from one case to the other, but gamma W has approximately the same value which equals the energy obtained in the (111) direction. (Author)

Descriptors :   (*COPPER, CRYSTALLOGRAPHY), (*SPECTROSCOPY, COPPER), (*ULTRASONIC RADIATION, COPPER), (*CRYSTAL DEFECTS, COPPER), ADSORPTION, EXCITATION, HEAT OF ACTIVATION, RELAXATION TIME, FREQUENCY, SINGLE CRYSTALS, CRYSTALS, SWEDEN

Distribution Statement : APPROVED FOR PUBLIC RELEASE