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Determination of the Piezospectroscopic Coefficients for Chromium‐Doped Sapphire
Author(s) -
He Jun,
Clarke David R.
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08493.x
Subject(s) - tensor (intrinsic definition) , sapphire , cauchy stress tensor , ion , symmetry (geometry) , principal axis theorem , chemistry , materials science , physics , analytical chemistry (journal) , molecular physics , optics , geometry , mathematics , classical mechanics , quantum mechanics , laser , chromatography
The coefficients of the piezospectroscopic tensor for a 0.05 wt% ruby are evaluated by direct measurement of the frequency shift for uniaxial compression along the three principal crystallographic directions and for loading in the three principal shear directions. Although the numerical value of the trace of the tensor is the same äs previously reported, the piezospectroscopic coefficients along the c and m directions are slightly different. Contrary to expectation from the rotational symmetry of sapphire about the c axis, the coefflcient along the a direction was found to be different from that along the m direction. It also varies nonlinearly with strain in the a direction. The difference is attributed to the applied stress breaking the rotational symmetry about the c axis and is interpreted in terms of the relative motion of the Cr 3+ ion with respect to the nearest‐neighbor oxygen ions. An additional finding is that there is a signiflcant difference in the piezospectroscopic tensor for the Rl and R2 lines. This will facilitate a more complete determination of the stress tensor from fluorescence measurements than has hitherto been possible.