Using a diamond anvil cell, the variable-frequency alternate current impedance spectrum of β -boron has been measured upon increasing the pressure from 3.2 to 27.5 GPa. The analysis has established that both the bulk resistance and the grain boundary resistance of β -boron smoothly decrease with the pressure, and that a remarkable phenomenon of discontinuity occurs at 23.9 GPa; this critical value has been interpreted as the pressure threshold above which the van der Waals forces and the interactions between the β -boron grain boundaries significantly emerge. Thence, the grain boundary contribution to the total resistance dramatically declines and results in an enhanced conduction. Besides, the β -boron sample impedance imaginary part exhibits a typical iron-core inductor frequency characteristic.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)