Static compression of rare earth metal holmium to 282 GPa

Abstract

ABSTRACT The phase transitions and equation of state measurements were carried out on rare earth metal Holmium (Ho) to 282 GPa using toroidal diamond anvils thereby doubling the pressure range to which it has been studied previously. The first set of experiment employed standard beveled diamond anvils utilizing copper as an x-ray pressure standard to 217 GPa. The second set of experiment employed toroidal diamond anvils utilizing platinum as an x-ray pressure standard to 282 GPa. The recently proposed 16-atom orthorhombic structure (oF16) appeared to be stable between 103 and 282 GPa. The scaled axial ratio (c/a) shows a narrow range of variation of 1.58 ± 0.05 for the five known crystalline phases of Ho to 282 GPa. The experimental equation of state of Ho is presented up to a threefold volume compression V/Vo = 0.322.