CONCENTRATION-DEPENDENCE OF THE DEBYE TEMPERATURE IN EXTENDED SOLID-SOLUTIONS NEAR THE CRYSTAL-TO-GLASS TRANSITION

In order to study the change of the phonon spectrum near the crystal-to-glass transition in extended solid solutions, the low temperature specific heat of rapidly quenched crystalline NbPd (0 less-than-or-equal-to X(Pd) less-than-or-equal-to 0.52) and ball-milled ZrAl (0 less-than-or-equal-to X(Al) less-than-or-equal-to 0.5) was measured far from equilibrium. The results show in both cases a drastic decrease of the Debye temperature prior to structural transformations (i.e., bcc --> fcc for NbPd at x(Pd) congruent-to 0.44 and hcp --> amorphous for ZrAl at X(Al) congruent-to 0.2) indicating a large elastic softening as a precursor of an underlying instability.