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1990

Santa Clara University

Articles 1 - 3 of 3

Full-Text Articles in Physics

Hyper-Resistivity To Global-Superconductivity Transition By Annealing In Quench-Condensed Pb Films, Richard P. Barber Jr., Rolfe Eldridge Glover Iii Oct 1990

Hyper-Resistivity To Global-Superconductivity Transition By Annealing In Quench-Condensed Pb Films, Richard P. Barber Jr., Rolfe Eldridge Glover Iii

Physics

The rapid rise in resistance occurring in barely conducting quench-condensed Pb films cooled through temperatures characteristic of the bulk superconducting transition is found to be strongly current dependent, the resistance increasing rapidly with decreasing current and temperature. Annealing the same film at temperatures below 40 K changes the behavior to that of a conventional superconductor with resistance that drops as the film current and temperature decrease. Experimental evidence suggests this results from a transition from quasiparticle-dominated to Josephson-dominated tunneling.


Observation Of Ballistic Phonons In Silicon Crystals Induced By Α Particles, Betty A. Young, Blas Cabrera, Adrian T. Lee Jun 1990

Observation Of Ballistic Phonons In Silicon Crystals Induced By Α Particles, Betty A. Young, Blas Cabrera, Adrian T. Lee

Physics

We have observed the ballistic-phonon-focusing pattern along the [100] axis of a 1-mm-thick silicon crystal using α-particle bombardment as the phonon source. These experiments on phonon-mediated particle detection are performed in vacuum at about 400 mK and use titanium-superconducting-transition-edge phonon sensors on the crystal surfaces. The ballistic time of flight is confirmed in one experiment and the focusing patterns are spatially resolved in another. These data indicate that about 1/3 of the phonon energy striking the back face during the first μsec is ballistic.


Energy Deposition Of Energetic Silicon Atoms Within A Silicon Lattice, P. Zecher, D. Wang, J. Rapaport, C. Jeff Martoff, Betty A. Young Apr 1990

Energy Deposition Of Energetic Silicon Atoms Within A Silicon Lattice, P. Zecher, D. Wang, J. Rapaport, C. Jeff Martoff, Betty A. Young

Physics

The energy dependence of the ionization produced in silicon by recoiling silicon atoms was measured in the 4–54-keV energy interval. It is found that the fraction of the recoil energy that is dissipated as ionization follows an E1/2 dependence which agrees well with the predictions of the theory of Lindhard et al. [Mat. Fys. Medd. 33, 10 (1963)].