High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

Journal Article · Thu Apr 07 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4945704· OSTI ID:22594575

Montgomery, J. M.; Samudrala, G. K.; Vohra, Y. K. ^[1]; Velisavljevic, N. ^[2]

---

1. Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294 (United States)
2. Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)

A 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, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm 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.

• OSTI ID: 22594575
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 13; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BORON
CHEMICAL VAPOR DEPOSITION
COOLING
DIAMONDS
DOPED MATERIALS
EQUATIONS OF STATE
GADOLINIUM
HCP LATTICES
HEATERS
HEATING
IMAGES
LAYERS
PHASE DIAGRAMS
PRESSURE RANGE GIGA PA
SAPPHIRE
SURFACES
SYNCHROTRONS
TIME RESOLUTION
X RADIATION
X-RAY DIFFRACTION