Shubnikov-de Haas Effect and Magnetic Breakdown in Be

Magnetic breakdown in the basal plane of Be was investigated in fields up to 150 kG. Geometrical aspects of the open orbits caused by breakdown are discussed. An estimate of 30 kG for the characteristic breakdown field is obtained by applying the theory of Falicov et al. Shubnikov-de Haas frequency measurements are reported for the central-cigar cross section. These measurements are relevant to a recent conjecture that the Onsager-Lifshitz quantization scheme may be violated in the presence of magnetic breakdown

de Haas-van Alphen Effect in Dilute Beryllium-Copper Alloys

The de Haas-van Alphen effect was investigated in pure beryllium and in Be-Cu alloys containing up to 0.34 at.% Cu. The extremal cross-sectional areas of the cigar-shaped third-band electron pieces of Fermi surface decreased with alloying. The areas of the coronet-shaped second-band hole piece increased with alloying. The magnitude of the area changes were compared with rigid-band-theory predictions. Corrections for lattice-parameter changes were included when possible. In the low-concentration limit, the theory is able to account for the observed area changes. For the highest-concentration alloy, there are deviations, for all areas measured, to greater changes than are predicted by the theory. However, further data in the higher-concentration region (≳0. 3 at.% copper) are needed to verify this trend. Amplitude measurements were made to obtain cyclotron masses and scattering temperatures. Within experimental error, the masses were found to be independent of alloying. A significant anisotropy over the Fermi surface was observed in the rate of change of scattering temperature with respect to copper concentration. An analysis was made to determine the scattering rate due to copper impurities for the four orbits studied. The results indicate that this scattering rate is considerably larger for the two cigar orbits than it is for the two coronet orbits. The relative values of the scattering times as determined by the de Haas-van Alphen effect and residual-resistivity measurements were compared with the free-electron theory of Brailsford. Only order-of-magnitude agreement was found