Compressibility of strontium orthophosphate Sr3(PO4)2 at high pressure
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High pressure in situ synchrotron X-ray diffraction experiment of strontium orthophosphate Sr3(PO4)2 has been carried out to 20.0 GPa at room temperature using multianvil apparatus. Fitting a third-order Birch–Murnaghan equation of state to the P–V data yields a volume of V 0 = 498.0 ± 0.1 Å3, an isothermal bulk modulus of K T = 89.5 ± 1.7 GPa, and first pressure derivative of K T ′ = 6.57 ± 0.34. If K T ′ is fixed at 4, K T is obtained as 104.4 ± 1.2 GPa. Analysis of axial compressible modulus shows that the a-axis (K a = 79.6 ± 3.2 GPa) is more compressible than the c-axis (K c = 116.4 ± 4.3 GPa). Based on the high pressure Raman spectroscopic results, the mode Grüneisen parameters are determined and the average mode Grüneisen parameter of PO4 vibrations of Sr3(PO4)2 is calculated to be 0.30(2).
KeywordsSr3(PO4)2 Equation of state Synchrotron X-ray diffraction High pressure
We thanks Prof. M. Matsui for his editorial handling and suggestion. Critical comments and suggestion from two anonymous reviewers are helpful to improve the manuscript. The X-ray diffraction measurements were conducted at BL04B1, SPring-8, Japan (proposal no. 2010A1314). This work was financially supported by National Natural Science Foundation of China (grant nos., 40973045 and 41010104017).
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