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

Technical Report · Thu Dec 19 23:00:00 EST 1985

OSTI ID:5774631

Levy,

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 a perpendicular magnetic field. At 4.2 K the film appears to have an upper critical field of about 60 kG. Bulk ultrasonic measurements were in the series Er(1-x)Ho(x)Rh/sub 4/B/sub 4/. At 15 MHz, a broad peak in attenuation, due to a relaxation mechanism associated with the Ho ions, is observed around 10 K. It moves to lower temperatures as x is decreased. An increase in attenuation is observed in the superconducting state of those alloys which are ferromagnetic superconductors. This increase may be due to superconducting screening of crystalline-field effects that inhibit spin-phonon interaction in the normal state. Preliminary measurements of the acousto-electric coupling of SAW with an Al granular film, which is held 15 micron's above the SAW, indicate that at 19 MHz the attenuation increases when the film becomes superconducting. This is an unexpected result since at this frequency the attenuation is expected to decrease when the film becomes superconducting.

• Research Organization: Wisconsin Univ., Madison (USA). Plasma Physics Research
• OSTI ID: 5774631
• Report Number(s): AD-A-164004/4/XAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ATTENUATION
CHARGED PARTICLES
CRYSTALS
CURRENTS
DIRECT CURRENT
ELECTRIC CURRENTS
FERROMAGNETIC MATERIALS
FILMS
INTERACTIONS
IONS
MAGNETIC FIELDS
MAGNETIC MATERIALS
MATERIALS
PHONONS
QUASI PARTICLES
RELAXATION
SOUND WAVES
SUPERCONDUCTORS
THIN FILMS
ULTRALOW TEMPERATURE