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

Technical Report · Mon Apr 22 00:00:00 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
FERROMAGNETIC MATERIALS
SUPERCONDUCTIVITY
LEAD
NITRIDES
SUPERCONDUCTORS
ACOUSTIC MEASUREMENTS
THIN FILMS
VANADIUM
ATTENUATION
CRYOGENICS
MAGNETIC FIELDS
MONOCRYSTALS
NIOBIUM
SOUND WAVES
TRANSITION TEMPERATURE
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
MAGNETIC MATERIALS
MATERIALS
METALS
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties