Giant heat release and time-dependent thermal expansion of Nb-Ti-D

Glasslike anomalies of low-temperature thermal properties were observed fbr the polycrystalline Nb(37)Ti(63)alloy and Nb37Ti63 doped with deuterium. A giant heat release effect was found in (Nb-Ti)(92)D-8 Corresponding to a s pectral density, of two level steins of 7.8 10(45) J(-1) m(-3). After rapid cooling of the sample a length relaxation with a quadratic dependence on t he starting temperature wets detected obeying a logarithmic time dependence . The results fit to the standard tunneling model assuming a temperature an d time independent Gruneisen parameter. A constant Gruneisen parameter is c ompatible with a constant deformation potential gamma but requires partial derivative lambda/partial derivativeV to depend on Delta/Delta (o,) For bot h systems the thermal expansion coefficient exhibits a linear temperature t erm in the superconducting state dominating below 1 K.