High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2016-04-07 |
| Journal | Journal of Applied Physics |
| Authors | Jeffrey Montgomery, Gopi Samudrala, Nenad Velisavljevic, Yogesh K. Vohra |
| Institutions | University of Alabama at Birmingham, Los Alamos National Laboratory |
| Citations | 5 |
Abstract
Section titled āAbstractāA boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, Ī±Sm, and dhcp phases. Under this temperature cycling, the hcp ā Ī±Sm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0-10 GPa and 300-650 K.