TY - JOUR
T1 - Crystalline coherence length effects on the thermal conductivity of MgO thin films
AU - Meyer, Kelsey E.
AU - Cheaito, Ramez
AU - Paisley, Elizabeth
AU - Shelton, Christopher T.
AU - Braun, Jeffrey L.
AU - Maria, Jon Paul
AU - Ihlefeld, Jon F.
AU - Hopkins, Patrick E.
N1 - Publisher Copyright:
© 2016, Springer Science+Business Media New York.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Phonon scattering in crystalline systems can be strongly dictated by a wide array of defects, many of which can be difficult to observe via standard microscopy techniques. We experimentally demonstrate that the phonon thermal conductivity of MgO thin films is proportional to the crystal’s coherence length, a property of a solid that quantifies the length scale associated with crystalline imperfections. Sputter-deposited films were prepared on (100)-oriented silicon and then annealed to vary the crystalline coherence, as characterized using x-ray diffraction line broadening. We find that the measured thermal conductivity of the MgO films varies proportionally with crystalline coherence length, which is ultimately limited by the grain size. The microstructural length scales associated with crystalline defects, such as small-angle tilt boundaries, dictate this crystalline coherence length, and our results demonstrate the role that this length scale has on the phonon thermal conductivity of thin films. Our results suggest that this crystalline coherence length scale provides a measure of the limiting phonon mean free path in crystalline solids, a quantity that is often difficult to measure and observe with more traditional imagining techniques.
AB - Phonon scattering in crystalline systems can be strongly dictated by a wide array of defects, many of which can be difficult to observe via standard microscopy techniques. We experimentally demonstrate that the phonon thermal conductivity of MgO thin films is proportional to the crystal’s coherence length, a property of a solid that quantifies the length scale associated with crystalline imperfections. Sputter-deposited films were prepared on (100)-oriented silicon and then annealed to vary the crystalline coherence, as characterized using x-ray diffraction line broadening. We find that the measured thermal conductivity of the MgO films varies proportionally with crystalline coherence length, which is ultimately limited by the grain size. The microstructural length scales associated with crystalline defects, such as small-angle tilt boundaries, dictate this crystalline coherence length, and our results demonstrate the role that this length scale has on the phonon thermal conductivity of thin films. Our results suggest that this crystalline coherence length scale provides a measure of the limiting phonon mean free path in crystalline solids, a quantity that is often difficult to measure and observe with more traditional imagining techniques.
UR - http://www.scopus.com/inward/record.url?scp=84982893757&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84982893757&partnerID=8YFLogxK
U2 - 10.1007/s10853-016-0261-5
DO - 10.1007/s10853-016-0261-5
M3 - Article
AN - SCOPUS:84982893757
SN - 0022-2461
VL - 51
SP - 10408
EP - 10417
JO - Journal of Materials Science
JF - Journal of Materials Science
IS - 23
ER -