The influence of hydrogen charging on the glassy low temperature properties of a polycrystalline NbTi-alloy

We measured the thermal conductivity, specific heat and heat release of pol ycrystalline Nb37Ti63 at low temperatures. Further we charged our sampler w ith hydrogen and investigated the influence of different charging concentra tions on these thermal properties. All physical features show low temperatu re behaviour similar to amorphous solids. The distribution parameter (P) ov er bar and the coupling constant gamma, extracted from the experimental dat a, indicate two different tunneling systems in NbTi and hydrogen charged Nb Ti. In hydrogen charged NbTi the distribution parameter varies nearly propo rtional to the hydrogen concentration. (C) 1999 Elsevier Science B.V. All r ights reserved.