Sound Velocity Measurement of Pure Iron under Earth's Core Conditions Using Dynamic Compression

Sound velocity measurement using transfer function method

Abstract The transfer function of a piezoelectric transducer, buffer rod and sample assembly is used to measure the sound velocity of solid materials. From the recorded transfer function, pulse echo patterns at frequencies of the passband of the input signal are reproduced after convoluting with monochromatic RF input signals. The time delay is obtained by performing pulse echo overlap and phas...

First-principles calculations of properties of orthorhombic iron carbide Fe7C3 at the Earths core conditions

Thermodynamics of hexagonal-close-packed iron under Earth’s core conditions

The free energy and other thermodynamic properties of hexagonal-close-packed iron are calculated by direct ab initio methods over a wide range of pressures and temperatures relevant to the Earth’s core. The ab initio calculations are based on density-functional theory in the generalized-gradient approximation, and are performed using the projector augmented wave approach. Thermal excitation of ...

Structure and dynamics of liquid iron under Earth’s core conditions

First-principles molecular-dynamics simulations based on density-functional theory and the projector augmented wave ~PAW! technique have been used to study the structural and dynamical properties of liquid iron under Earth’s core conditions. As evidence for the accuracy of the techniques, we present PAW results for a range of solid-state properties of lowand high-pressure iron, and compare them...

Constraints on Earth’s inner core composition inferred from measurements of the sound velocity of hcp-iron in extreme conditions

Hexagonal close-packed iron (hcp-Fe) is a main component of Earth's inner core. The difference in density between hcp-Fe and the inner core in the Preliminary Reference Earth Model (PREM) shows a density deficit, which implies an existence of light elements in the core. Sound velocities then provide an important constraint on the amount and kind of light elements in the core. Although seismolog...