Structural and insulator-to-metal phase transition at 50 GPa in GdMnO 3

We present a study of the effect of very high pressure on the orthorhombic perovskite GdMnO${}_{3}$ by Raman spectroscopy and synchrotron x-ray diffraction up to 53 GPa. The experimental results yield a structural and insulator-to-metal phase transition close to 50 GPa, from an orthorhombic to a metrically cubic structure. The phase transition is of first order with a pressure hysteresis of about 6 GPa. The observed behavior under very high pressure might well be a general feature in rare-earth manganites.