Calibration of Sm:YAG as an alternate high-pressure scale

The pressure-induced wavelength shift of a laser-excited fluorescence in samarium-doped yttrium aluminum garnet (Sm:YAG) was compared with that of ruby to 26 GPa at room temperature. Because the fluorescence wavelength for Sm:YAG has a negligible temperature dependence, it provides a better pressure scale for diamond anvil cell applications than ruby under high-temperature conditions. However, the overall intensity of the Sm:YAG fluorescence is less than that for ruby. A Gaussian–Lorentzian profile was chosen to analyze the fluorescence spectra. The Sm:YAG fluorescence wavelength exhibits an approximately linear pressure dependence (3.07±0.45 Å/GPa) only to 20 GPa at room temperature. A polynomial fit for all data to 26 GPa gives P(GPa)=−10 280(λ/λ0−1)2 +2085(λ/λ0−1), with a rms misfit of 0.14 GPa.