Influence of electron drag on dislocation motion in superconducting niobium

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7220119

Tregilgas, J H

Conduction electrons in metals produce a drag on moving dislocations which contributes to the flow stress of a metal. This flow stress contribution can be measured in superconductors because the electron drag can be changed between the normal and superconducting states by using a magnetic field. Using this technique both the temperature dependence and the field dependence of the change in flow stress have been measured in a high purity bcc transition metal, niobium. Results show that the change in flow stress between about 2K and 92K for niobium varies in a linear manner over this temperature range, which is very different from the behavior observed in non-transition metal superconductors. This suggests that, in addition to electron drag, another process which is, also, dependent on temperature affects the motion of dislocations in niobium. The field dependence of the change in flow stress between the superconducting state and mixed state for niobium has been found to be proportional root(1 - B/H/sub c2/). This result is consistent with the field dependence of the acoustic attenuation, and implies that dislocations in niobium are moving as high velocity elastic waves.

• Research Organization: Connecticut Univ., Storrs (USA)
• OSTI ID: 7220119
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
DRAG
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FLOW STRESS
LINE DEFECTS
METALS
MIXED STATE
NIOBIUM
PHYSICAL PROPERTIES
REFRACTORY METALS
STRESSES
SUPERCONDUCTIVITY
TRANSITION ELEMENTS