LOW-TEMPERATURE SPECIFIC-HEAT OF NEAR-EQUIATOMIC NI-RICH B19'-TINI-ALLOYS

The total DOS has been calculated for B 19'-TiNi-alloys using three di fferent compositions (50.0, 51.6 and 53.1at.% Ni) by means of the line arized muffin-tin-orbital (LMTO) method. No drastic increase in the Fe rmi-level DOS has been found at 51.6 at.% Ni (with respect to the comp osition of 50.0 at.% Ni). There is a slight increase at 53.1 at.% Ni. The electron-phonon mass enhancement factor (lambda(ep)) has in this c ase only a small contribution to the electronic coefficient of the low -temperature specific heat (gamma). According to our calculations, it is not the composition in itself which can cause the large experimenta l value of gamma at 51.5 at.% Ni. Our results agree with the view that it is not the high Fermi-level DOS but an anomaly in the electron-pho non system which is responsible for the composition-dependent variatio n of the martenstitic transition temperature (T-Ms). It is probable th at the large experimental value of gamma at 51.5 at.% Ni is caused by impurities: by precipitates or impurity phases. (C) 1998 Elsevier Scie nce Ltd. All rights reserved.