Structural investigation of amorphous materials at high pressures using the diamond anvil cell

A modified diamond anvil cell (DAC) is used for structural studies of amorphous materials at high pressures using a monochromatic synchrotron x-ray beam. The DAC modification includes (1) the use of x-ray transparent seats for a large angular opening for x-ray scattering, and (2) the introduction of a boron gasket insert to increase the sample thickness and to minimize the gasket–hole deformation. A procedure for absorption correction and background subtraction in DAC experiments is described, together with an optimization process for obtaining accurate data of the structure factor and the corresponding pair distribution function. Data for amorphous iron at 67 GPa are presented for demonstration. It is shown that quantitative structural data can be determined for amorphous materials at very high pressures using the DAC. The apparatus should be also useful for structural studies of liquids at high pressures.