Thin superconducting-film characterization by surface acoustic waves. Research progress report, 30 September 1984-22 April 1985

Technical Report · Sun Apr 21 23:00:00 EST 1985

OSTI ID:6129197

Levy, M

Both the dc electrical resistivity and the attenuation of surface acoustic waves (SAW) were measured in the superconducting state of a granular lead film as a function of an applied magnetic field normal to the film plane. At 4.2 K the data appear to yield an upper critical field of about 60 kG and a lower critical field of about 20 kG. A theoretical model that takes into account renormalization has been developed for explaining the SAW attenuation in a superconducting NbN film with a sheet resistivity of 30 k ohms/sq. Bulk ultrasonic measurements in the ferromagnetic superconductors Er/sub x/Ho/sub 1-x/RH4B4 indicate that spin phonon interaction increases in the superconducting state of these ternary compounds. Ultrasonic measurements in very pure vanadium single crystals provide low-temperature data which yield a zero temperature energy gap 2 Delta(0) that is very close to the BCS value of 3.5 kT/sub c/ but the data close to the superconducting transition temperature T/sub c/ would yield 2 Delta (0) = 4.2 kT/sub c/. A theoretical model is being investigated to ascertain if it will resolve this apparent discrepancy.

• Research Organization: Wisconsin Univ., Madison (USA). Plasma Physics Research
• OSTI ID: 6129197
• Report Number(s): AD-A-158311/1/XAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ACOUSTIC MEASUREMENTS
ATTENUATION
CRYOGENICS
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FERROMAGNETIC MATERIALS
FILMS
LEAD
MAGNETIC FIELDS
MAGNETIC MATERIALS
MATERIALS
METALS
MONOCRYSTALS
NIOBIUM
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
SOUND WAVES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
THIN FILMS
TRANSITION ELEMENTS
TRANSITION TEMPERATURE
VANADIUM