Synthetic MgAl2O4 (spinel) at high pressure conditions (0.0001-30 GPa): a X-ray powder diffraction by synchrotron radiation

The equation of state and the structural behavior of synthetic MgAl2O4 have been investigated using synchrotron X-ray powder diffraction data collected to 30 GPa at room temperature. The Birch-Murnaghan, Vinet, and Poirier-Tarantola models have been fitted to the observed P-V data. The Birch-Murnaghan equation of state, with V0 fixed at its experimental value, yields K0 = 190.8(±1.2) GPa, K′0 = 6.77(±0.15) and K″0 = -0.075 GPa-1 (implied value). The compression of spinel occurs with a negligible change of the fractional coordinate of oxygen. Therefore the structural shrinking is a function of cell edge shortening alone. The results presented here are compared with those from the literature.