Experimental studies of induced superconductivity in normal metals by proximity effect tunneling

Thesis/Dissertation · Mon Jan 01 00:00:00 EST 1979

OSTI ID:5830656

O'Donovan-Vojtovic, B F

In chapter 1 we describe how a normal metal can become a superconductor by the Proximity Effect. The density of states of a normal metal in good contact with a superconductor (N-S junction) is due to two separate contributions. 1) The Andreev scattering at the N-S interface produces interference in N and thus an oscillatory function in the density of states. 2) The induced pair potential in N shows structure at energies associated with the phonon modes of N. Electron tunneling is explained in chapter 2 where it is shown that the conductance (dI/dV) of a tunnel junction is proportional to the density of states of both electrodes. The techniques and sample preparation are outlined in chapter 3. In addition a diagram is shown representing the circuit used to measure I vs V, first and second derivatives of a tunnel junction. The study of diffusion for the Sn-Pb system is studied in chapter 4 where we see that 200 A of Pb do not diffuse into 3000 A of Sn whereas 200 A of Sn diffuse into 3000 A of Pb. In chapter 5 the two contributions to the density of states described in chapter 1 are seen to be separables by the application of a magnetic field or by putting impurities in N. In chapter 6 the results of chapter 5 are used to measure the Fermi velocity in N. In chapter 7 trilayers junctions of the form Al-Ox-Ag-Cu-Pb or Al-Ox-Cu-Ag-Pb show normal phonon structures of only the metal adjacent to the oxide in addition to the interference of the electron wave-function produced in both normal metals. Finally in chapter 8 we look at N-Ox-S and N-Ox-N-S junctions in the gapless regime by the application of a magnetic field higher than the bulk critical field.

• Research Organization: California Univ., Los Angeles (USA)
• OSTI ID: 5830656
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
METALS
PROXIMITY EFFECT
SUPERCONDUCTING JUNCTIONS
ALUMINIUM
COPPER
DIFFUSION
ELECTRICAL PROPERTIES
EXPERIMENTAL DATA
LEAD
NITROGEN
OXIDES
SILVER
SULFUR
SUPERCONDUCTIVITY
TIN
TUNNEL EFFECT
CHALCOGENIDES
DATA
ELECTRIC CONDUCTIVITY
ELEMENTS
INFORMATION
JUNCTIONS
NONMETALS
NUMERICAL DATA
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
TRANSITION ELEMENTS
656102* - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)