Ultrasonic wave from high pressure and temperature experiments
Abstract
The Earth’s inner core shows distinct features, including low shear velocities and a high Poisson’s ratio, often linked to hcp-Fe (hexagonal close-packed iron) through high-pressure experiments and calculations. Premelting is proposed as a key mechanism behind the observed shear softening in hcp-Fe. This study uses magnesium, an hcp-structured analogue, to explore the effects of premelting on ultrasonic velocities. Premelting begins at ~0.97 times the melting temperature(Tm), leading to sharp nonlinear drops in shear (VS) and compressional (VP) velocities by 14.5% and 4%, respectively, with a ~13.3% increase in Poisson’s ratio. These findings, together with seismic and mineralogical data, suggest that premelting could account for the reduced VP and VS and increased Poisson’s ratio observed in the Earth’s inner core.
https://doi.org/10.5061/dryad.dv41ns27z
Description of the data and file structure
This data are used for paper "Profound Impact of Premelting in the hcp-Structured Earth's Inner Core". This data continue the experiments records (records.xlsx) and the travel time of ultrasonic wave (Ultrasonic wave For P-wave and Ultrasonic wave For S-wave) at different temperature.
Files and variables
File: data.zip
Description:
Experimental_records.xlsx contains a detailed log of the experimental procedures during ultrasonic wave measurements. It includes the time, temperature, file number, travel time, and heater power for each ultrasonic measurement.
Time: The timestamp when the data was recorded.
Temperature(degree centigrade): The sample temperature at the time of recording.
Frequency (Hz): The frequency of the ultrasonic wave used.
S-NO: The file number for the S-wave measurement.
Travel Time (s): The travel time of the reflected S-wave or P-wave within the sample.
Amplitude (V): The peak amplitude of the reflected S-wave or P-wave.
P-NO: The file number for the P-wave measurement.
Power (% in 2 KW): The applied heating power during the measurement.
The files in the Ultrasonic wave for P-wave and S-wave folder are raw data collected from the oscilloscope during ultrasonic velocity measurements at various temperatures. The file names correspond to the file numbers (NO.) listed in Experimental_records.xlsx.
Each ultrasonic wave file contains two columns:
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The first column represents the travel time (unit: seconds).
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The second column represents the wave amplitude (unit: volts).
Note regarding ERF: Due to issues with the oscilloscope cursor during the experiments, some data could not be accurately read directly from the oscilloscope screen in real time.