Lattice dynamics ofγ-Fe

Abstract

Large single crystals of fcc iron (y phase) were grown in situ and used to study the lattice dynamics of this phase of Fe by standard inelastic neutron scattering techniques. The phonon dispersion curves were measured along the [00$], [g'0], and [gg] symmetry directions at 1428 K. A selected number of phonon frequencies were also obtained at 1227 and 1640 K. We find that the measured dispersion curves are qualitatively similar to those of Ni and Ni03Feo 7 The 1428-K data were used to evaluate the elastic constants, the phonon density of states, and the lattice specific heat of y-Fe.

Force and Elastic Constants of Metals and Alloys

“…Radial and tangential force constants of α-Fe in the first ten coordination spheres, calculated in [34] with application of the TMMP of Animalu and used in calculations of elastic constants, are given in Table 6. Calculation results [34] of elastic constants for α-Fe, generally, in good agreement with the experimental data, and are close to the calculation results [36], where it were proceeded from first principles in the local density approximation (LDA) within the density functional theory and dynamic theory of an average field, which allows to calculate electronic and structural properties of materials, [37]. The same can be said about the calculation results of elastic constants for α-Fe [38].…”

High‐temperature viscoelastic relaxation in iron and its implications for the shear modulus and attenuation of the Earth's inner core

“…Single-crystal elastic constants for fcc-Fe at 1155øC derived from phonon dispersion curves measured by neutron diffraction [Zarestky and Stassis, 1987] (Table 7).…”

Dynamical stability of body center cubic iron at the Earth’s core conditions

“…The α-Fe phase is ferromagnetic at low temperatures. Above 1,185 K, iron is already paramagnetic (the Curie temperature of bcc-Fe is 1,044 K) until melting occurs (15,16). Under the application of pressure at room temperature, α-Fe undergoes a transition at 13 GPa to the hcp structure, the so-called ϵ-phase (17), accompanied by a loss of the ferromagnetic order (18).…”