Unconventional superconductivity in UBe13 probed by uniaxial stress

In order to examine the nature of the superconducting order parameter in UBe13, we measured the specific heat, C, as a function of temperature, T, under uniaxial stress along <100> axis, for both "L"-(T-c approximate to 0.75 K) and "H"-type (0.85less than or equal toT(c)less than or equal to 0.95 K) crystals. With increasing pressure, a linear decrease of the superconducting transition temperature, T-c, was observed (partial derivativeT(c)/partial derivativepsimilar or equal to8.5mK/GPa for "L"-type and partial derivativeT(c)/partial derivativepsimilar or equal to50mK/GPa for "H"-type) but no split of the transition could be resolved unambiguously for either of the two samples within our measurement resolution. (C) 2002 Elsevier Science B.V. All rights reserved