Microwave acoustic studies of materials in diamond anvil cell under high pressure

This paper presents an integrated measuring system combining a diamond anvil cell (DAC) and a high overtone bulk acoustic resonator (HBAR) operating at the microwave frequency band as 2.8-8.8 GHz. We have studied several metallic (W, Zr) and semiconductor (Si) samples under pressure up to & SIM;16 GPa. As an HBAR, we have used the "Al/Al0.72Sc0.28N/Mo/(100) diamond " structure utilizing a piezoelectric aluminum-scandium nitride film. We have observed that under pressure, the Q-factor of the HBAR decreases but remains at the value of 2500-3000, which is suitable for our experiments. It is demonstrated that the above system can be used for studying the behavior of various solids under high pressure, the pressure-induced phase transition in Zr, the registration of plastic deformations, and their relaxation in metals. Here, we discussed the phenomenon of an acoustic wave passing through a tungsten layer under a pressure of & SIM;5.5 GPa. The integrated DAC & HBAR measuring system has demonstrated some practical advantages over known ultrasonic systems combined with the DAC as the possibility of applying a microwave operational frequency, the measurement of a Q-factor change under pressure, and the miniature size of a sensitive HBAR element. The application of the built-in DAC & HBAR system will hopefully allow more accurate studies on materials in the GPa pressure range of a DAC. Published under an exclusive license by AIP Publishing.