SUPERCONDUCTING PHASE-DIAGRAMS OF UPT3 FROM ULTRASONIC VELOCITY-MEASUREMENTS

Superconducting phase diagrams of the heavy fermion compound UPt3 in t he H-T plane for the magnetic held at 90 degrees, 45 degrees and 0 deg rees to the c-axis were determined by high-resolution ultrasonic veloc ity measurements. Rich features observed in the complex phase diagrams provide many constraints on the identification of the symmetry class for the superconducting order parameter in this compound.