Ultrasonic measurements in the superconducting state of URu/sub 2/Si/sub 2/

Abstract

Measurements of attenuation, velocity, and AC susceptibility on a URu/sub 2/Si/sub 2/ single crystal in the frequency range from 32 to 300 MHz and the temperature range from 300 mK up to 25 K are reported. The measurements of ultrasound and AC susceptibility were performed on the same single crystal of URu/sub 2/Si/sub 2/ (0.37 cm long) in the vicinity of the Neel transition temperature T/sub N/ and the superconducting transition temperature T/sub c/. The results show sharp signatures at T/sub N/ and near T/sub c/. The measurements of both attention and velocity across the superconducting transition show an attenuation peak and jump, respectively. The results of a magnetic field sweep indicate that URu/sub 2/Si/sub 2/ may also show a magnetic-field-induced phase transition.<>