Anomalies in the enthalpy of freezing in alpha-phase indium—lead,due to brillouin-zone effects

The enthalpy of freezing has been measured with DTA using electrical calibration for 33 compositions of indium—lead in the range 6.9–7.9 at.% lead, at which range the electron—lattice interaction causes anomalies in several physical and structural properties. Enthalpies of mixing, ΔH_m^s, have been calculated. The results reveal three maximum and minimum pairs corresponding to partial shift of the Fermi surface to higher Brillouin zones in three steps at 7.1, 7.2 and 7.3–7.4 at.% lead. These details in the overlapping have not been found earlier. The observed change in ΔH_m^s in the steps is about 1 meV atoms^?1.