PAIR-BREAKING EDGE OF SUPERFLUID HE-3-B IN A MAGNETIC-FIELD

We have conducted ultrasound pulse transmission experiments to investigate the pair-breaking edge for superfluid B3 in a magnetic field. The experiments were performed at He3 temperatures below 0.4Tc, pressures between 6 and 29.3 bars, and ultrasound frequencies of 168.33, 137.6, and 107 MHz. We used both depressurization and demagnetization techniques to measure the linear and quadratic magnetic field dependence of the pair-breaking edge frequency. We obtain values for the Fermi-liquid interaction parameter F2a from the coefficient of the linear term. The quadratic term is due to the energy-gap distortion and its value is consistent with calculations of Schopohl and Tewordt. © 1990 The American Physical Society.