| About this Abstract |
| Meeting |
MS&T23: Materials Science & Technology
|
| Symposium
|
Mesoscale Phenomena in Functional Polycrystals and Their Nanostructures
|
| Presentation Title |
Acoustic Phonon Spectra Modification and Light Emission Properties of Rare Earth Doped Polycrystalline Alumina |
| Author(s) |
Javier Garay |
| On-Site Speaker (Planned) |
Javier Garay |
| Abstract Scope |
M. Wingert, E. H. Penilla, F. Kargar, A. A. Balandin and J. E. Garay
Point defects and grain boundaries can scatter phonons and reduce the thermal conductivity of dielectrics. Single crystal alumina (often referred to as sapphire) has a relatively high thermal conductivity. We have developed material processing methods that result in polycrystalline alumina (PCA) doped with higher than equilibrium concentrations of rare earth (RE) dopant atoms. We compare the thermal properties of single crystal and polycrystalline alumina using thermal conductivity measurements and Brillouin—Mandelstam spectroscopy (BMS). The results confirm RE incorporation and that this relatively low concentration of RE atoms produces a significant change in the acoustic phonon spectrum. The velocity of the transverse acoustic phonons decreases by ~600 m/s at the RE density of only 0.1%. We discuss the results with regard to the tunability of the phonon spectrum and implications on the thermal conductivity in PCA. |