Anisotropic lattice thermal expansion of PbFeBO4: A study by X-ray and neutron diffraction, Raman spectroscopy and DFT calculations
- Univ. of Bremen (Germany)
- National Univ. of Mar del Plata (Argentina)
- Inst. Laue-Langevin (ILL), Grenoble (France)
- Univ. of Nevada, Las Vegas, NV (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
We present the lattice thermal expansion of mullite-type PbFeBO4 in this study. The thermal expansion coefficients of the metric parameters were obtained from composite data collected from temperature-dependent neutron and X-ray powder diffraction between 10 K and 700 K. The volume thermal expansion was modeled using extended Grüneisen first-order approximation to the zero-pressure equation of state. The additive frame of the model includes harmonic, quasi-harmonic and intrinsic anharmonic potentials to describe the change of the internal energy as a function of temperature. Moreover, the unit-cell volume at zero-pressure and 0 K was optimized during the DFT simulations. Harmonic frequencies of the optical Raman modes at the Γ-point of the Brillouin zone at 0 K were also calculated by DFT, which help to assign and crosscheck the experimental frequencies. The low-temperature Raman spectra showed significant anomaly in the antiferromagnetic regions, leading to softening or hardening of some phonons. Selected modes were analyzed using a modified Klemens model. The shift of the frequencies and the broadening of the line-widths helped to understand the anharmonic vibrational behaviors of the PbO4, FeO6 and BO3 polyhedra as a function of temperature.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC05-00OR22725; FG 3606GO8636; EE-0000269; DEFG36-05GO08502; FC08-01NV14049
- OSTI ID:
- 1185585
- Alternate ID(s):
- OSTI ID: 1556557
- Journal Information:
- Materials Research Bulletin, Vol. 59, Issue C; ISSN 0025-5408
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Thermal expansion of mullite-type Bi{sub 2}Al{sub 4}O{sub 9}: A study by X-ray diffraction, vibrational spectroscopy and density functional theory
Anisotropic thermal expansion and anharmonic phonon behavior of mullite-type Bi{sub 2}Ga{sub 4}O{sub 9}