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Title: Crystallite growth limits in amorphous oxides
Abstract Post deposition thermal annealing of amorphous coatings improves optical properties of dielectric mirrors. However, excessive temperatures cause crystallization, resulting in a degradation of mechanical and optical properties. Therefore, annealing is limited to temperatures ‘below’ the crystallization threshold. The threshold is determined by x-ray diffraction (XRD) measurement which requires a significant amount of crystallized material for detection, yet it has been shown that a population of crystallites may exist in otherwise amorphous coatings below the threshold temperature. In this study XRD measurements show crystallites that grow during annealing within amorphous oxide coatings to a limited and predictable size predicated on the difference in density between the crystal and the surrounding amorphous phase and the average material’s Young’s modulus. These crystallites may be the point-like, extremely weak scatterers revealed in the LIGO test masses when imaged off-axis.  more » « less
Award ID(s):
2011710 2309294
PAR ID:
10483137
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
IOP Science
Date Published:
Journal Name:
Classical and Quantum Gravity
Volume:
41
Issue:
2
ISSN:
0264-9381
Page Range / eLocation ID:
025003
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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