Stability field of the orthorhombic perovskite type of MgSiO3

Stability field of the orthorhombic perovskite type of MgSiO3 was studied using an in situ x‐ray observation technique. It was revealed that the orthorhombic perovskite structure is stable from 24 GPa to 36 GPa below 1900 K. This result indicates that the orthorhombic perovskite is the dominant phase of MgSiO3 throughout the lower mantle.