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Title: High-pressure behavior and thermoelastic properties of niobium studied by in situ x-ray diffraction

In situ synchrotron energy dispersive x-ray diffraction (XRD) experiments on Nb have been conducted at pressures up to 6.4 GPa and temperatures up to 1073 K. From the pressure-volume-temperature measurements, thermoelastic parameters were derived for the first time for Nb based on the thermal pressure (ΔP{sub th}) equation of state (EOS), modified high-T Birch-Murnaghan EOS, and Mie-Grüneisen-Debye EOS. With the pressure derivative of the bulk modulus K{sub T}{sup ´} fixed at 4.0, we obtained the ambient isothermal bulk modulus K{sub T0}=174(5) GPa, the temperature derivative of bulk modulus at constant pressure (∂K{sub T}/∂T){sub P}=-0.060(8) GPa K⁻¹ and at constant volume (∂K{sub T}/∂T){sub V}=-0.046(8) GPa K⁻¹, the volumetric thermal expansivity α{sub T}(T)=2.3(3)×10⁻⁵+0.3(2)×10⁻⁸T (K⁻¹), as well as the pressure dependence of thermal expansion (∂α/∂P){sub T}=(₋2.0±0.4)×10⁻⁶ K⁻¹ GPa⁻¹. Fitting the present data to the Mie-Grüneisen-Debye EOS with Debye temperature Θ₀=276.6 K gives γ₀=1.27(8) and K{sub T0}=171(3) GPa at a fixed value of q=3.0. The ambient isothermal bulk modulus and Grüneisen parameter derived from this work are comparable to previously reported values from both experimental and theoretical studies. An in situ high-resolution, angle dispersive XRD study on Nb did not indicate any anomalous behavior related to pressure-induced electronic topological transitions at ~5 GPa asmore » has been reported previously.« less
Authors:
;  [1] ;  [2] ; ;  [3] ;  [1] ;  [4] ;  [2] ;  [5]
  1. Mineral Physics Institute, State University of New York, Stony Brook, New York 11794 (United States)
  2. Department of Materials Science and Engineering, State University of New York, Stony Brook, New York 11794 (United States)
  3. Department of Geosciences, State University of New York, Stony Brook, New York 11794 (United States)
  4. (China)
  5. (United States)
Publication Date:
OSTI Identifier:
22306167
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DEBYE TEMPERATURE; EQUATIONS OF STATE; NIOBIUM; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; RESOLUTION; SYNCHROTRON RADIATION; TEMPERATURE MEASUREMENT; THERMAL EXPANSION; THERMOELASTICITY; X-RAY DIFFRACTION