Thermal property characterization of single crystal diamond with varying isotopic composition
The mirage-effect/thermal wave technique as a modern technique for thermal property characterization is described. The thermal diffusivity of a material is determined by measuring the time and space varying temperature distribution (thermal wave) in the material generated by an intensity modulated heating laser beam. These thermal waves are detected through the deflection of a probe laser beam due to modulation of gradient of the index of refraction (mirage effect) either in the air above the specimens (the in-air technique) or in the specimen itself (the in-solid technique). Three-dimensional theories, for both in-air and in-solid mirage techniques, are represented. In order to extract the material parameters by comparing the theory with experimental data, an extensive data analysis procedure based on multiparameter-least-squares has been developed. The experimental and data analysis details are discussed. Topics concerns with the quality and reliability of the measurements are addressed. This technique has been successfully applied to the thermal property characterization of single crystal diamond with varying isotope contents. The results showed a 50% enhancement in the thermal conductivity by removal of C[sup 13] content from 1.1% to 0.1% in diamond at room temperature. The technique has also been adapted to function in cryogenic temperatures. The temperature dependence of thermal conductivity in the temperature range 80-378K for natural IIA specimen and 187-375K for isotopically enriched specimen are obtained, the former results agree with previous works and the latter results demonstrate the isotope effect on the thermal conductivity of single crystal diamond consistently in a large temperature range. The physical source of this enhancement in diffusivity due to the isotope effect in diamond is discussed. The discussion is based on the full Callaway's theory with emphasizing the role of N-processes in the phonon scattering mechanism.
- Research Organization:
- Wayne State Univ., Detroit, MI (United States)
- OSTI ID:
- 7165547
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DIAMONDS
ISOTOPE RATIO
THERMODYNAMIC PROPERTIES
MONOCRYSTALS
TEMPERATURE DISTRIBUTION
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THERMAL CONDUCTIVITY
THERMAL DIFFUSIVITY
CARBON
CRYSTALS
ELEMENTAL MINERALS
ELEMENTS
MINERALS
NONMETALS
PHYSICAL PROPERTIES
TEMPERATURE RANGE
360606* - Other Materials- Physical Properties- (1992-)