Experimental studies of nonequilibrium phase transitions in superconducting Pb films in the ultrashort time domain

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:7111542

Hu, Xinhua

The author was specifically concerned with the phase transitions from the superconducting to the normal state (and vice versa) under nonequilibrium conditions. These processes are created by an interaction between laser pulses, with durations from 100 fs to 70 ps, and superconducting films. The wavelengths of the laser output are between 532 and 630 nm. First studied was the resistive response of superconducting Pb films The relaxation of the superconducting order parameter in Pb at temperatures from 3K up to {Tc} was investigated with a temporal resolution of 1 ns. The dependences of the transient signals on the ambient temperature, laser irradiance, and bias current were determined. In another set of experiments, a transient electric field was generated and studied near the surface of a superconducting Pb film with picosecond laser pulses. Using the electro-optic sampling technique with subpicosecond time resolution, the rise-time of the transient electric field is determined to be {le} 1 ps. The transient thermoreflectivity of Pb films at low temperatures was also measured by 100 femtosecond laser pulses.

• Research Organization: California Univ., Irvine, CA (United States)
• OSTI ID: 7111542
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LEAD
PHASE TRANSFORMATIONS
SUPERCONDUCTING FILMS
ELECTRIC FIELDS
LASER RADIATION
ORDER PARAMETERS
REFLECTIVITY
SURFACES
TEMPERATURE RANGE 0000-0013 K
TRANSITION TEMPERATURE
ELECTROMAGNETIC RADIATION
ELEMENTS
FILMS
METALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SURFACE PROPERTIES
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
360102* - Metals & Alloys- Structure & Phase Studies