Low temperature ultrasonic study of hydrogen in niobium

Thesis/Dissertation · Mon Jan 01 00:00:00 EST 1979

DOI:https://doi.org/10.2172/6319798· OSTI ID:6319798

Poker, David Brian ^[1]

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1. Univ. of Illinois, Urbana-Champaign, IL (United States)

Measurements were made of the velocity and attenuation of ultrasonic waves in niobium containing 1000 ppM oxygen with additional concentrations of hydrogen, to determine the properties of a relaxation of the hydrogen which appears below 10 K. Measurements were made as a function of temperature, frequency, polarization of the ultrasonic wave, hydrogen isotope, and concentration of hydrogen and oxygen. The Birnbaum--Flynn model of hydrogen tunnelling is modified to take into account the trapping of hydrogen by interstitial impurities. An Orbach process is proposed for a relaxation between the degenerate first excited states. Three parameters which are determined by the hydrogen ultrasonic attenuation data are sufficient to describe the properties of this model. The model correctly predicts the presence of unusual features of the relaxation which are not contained in a classical model of hydrogen motion over a potential barrrier; the decrease of the hydrogen relaxation strength at low temperatures, the decrease in velocity below the relaxation temperature without a corresponding effect in the attenuation, and the broadness of the deuterium decrement peak compared to that for hydrogen. A reasonable fit to the velocity data for low concentration of hydrogen is made by the model with no adjustable parameters. A fit to the heat capacity can be made with the addition of parameters representing the strain effects of the oxygen trapping.

• Research Organization: Univ. of Illinois at Urbana-Champaign, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-02-1198
• OSTI ID: 6319798
• Report Number(s): COO-1198-1247; TRN: 79-010028
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NIOBIUM
SUPERCONDUCTIVITY
ULTRASONIC WAVES
BAND THEORY
HYDROGEN ADDITIONS
OXYGEN ADDITIONS
RELAXATION
TRAPPING
ULTRALOW TEMPERATURE
WAVE PROPAGATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
METALS
PHYSICAL PROPERTIES
REFRACTORY METALS
SOUND WAVES
TRANSITION ELEMENTS
656102* - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)
360104 - Metals & Alloys- Physical Properties