Effect of Al Contents on Raman Spectra of MgSiO₃ Perovskite

To study the effect of aluminum (Al) content on the vibration properties of MgSiO3 bridgmanites, we synthesized a series of aluminous bridgmanite at pressures of 23-27 GPa, a constant temperature of 2000 K in a multi-anvil apparatus. X-ray diffraction measurement confirms that they crystallized into a single-phase bridgmanite. With increasing Al contents, wavenumbers of Raman modes of bridgmanite did not show significant shifts. However, their full width of half maximum (FWHM) of Raman modes significantly became larger, suggesting that cation order and disorder may occur because of Al substitutions of Mg and Si cations in the bridgmanite structure.