High-pressure phase transition detection in diamond anvil cell using the method of ellipsometry

It is suggested to use the ellipsometric technique to measure the electronic properties of static highly compressed matter. The information derived from this technique is important for the theoretical and phenomenological research for the equation of state. This diagnostic was found to be useful and sensitive for measuring pressure induced phase transitions. In particular, high-pressure ellipsometry with a diamond anvil cell was used to detect the α⇄e phase transition in iron. The polarization of the light reflected from an iron foil was analyzed in the pressure domain of 0–24 GPa and the α⇄e transition in compression and decompression was detected. These results are in good agreement with Mossbauer spectroscopy, x-ray diffraction, and resistivity measurements.