Listening to Magnetism: Using ultrasound at high pressures as a probe to study uranium intermetallics

Ultrasonic measurements have proved to be successful in many different fields including medical imaging, navigation and acoustic microscopy. In condensed matter physics, they can be used to study electronic and magnetic properties of intermetallic materials. In particular, UGe2 is of special interest since it exhibits a host of exciting physical effects such as pressure induced superconductivity and quantum criticality. These effects are still not fully explained and require more investigation. However, probing the phase diagram of UGe2 remains a technical challenge. In my talk, I will explain how ultrasound is produced, measured and analysed to quantify materials properties. I will also discuss the design of a new pressure cell which has been developed specifically for ultrasonic measurements. The novelty of the design lays mainly in the ability to measure ultrasonic velocities in a single crystal at low temperatures (down to 2K) and high-pressures (up to 5GPa). The results of the experiment are to contribute to the explanation of unconventional superconductivity.