Specific heat of bccMo1−xTcx

Abstract

The low-temperature specific heats of four compositions of bcc ${\mathrm{Mo}}_{1-x}{\mathrm{Tc}}_x$ ($x=0.25, 0.45, 0.50, \mathrm{and} 0.54$) have been measured. Results indicate that the large normalized energy gaps $\frac{2\Delta }{k{T}_c}$ found previously in both bcc and $A-15\mathrm{}$ ${\mathrm{Mo}}_{0.4}$ ${\mathrm{Tc}}_{0.6}$ exist also at other compositions in the bcc phase away from the bcc phase boundary at $x=0.6\mathrm{}$. A possible cause of this strongcoupling behavior is the presence of a very sharp $d$-band for $0.5<~x<~0.6$ as revealed by the linear term in the specific heat for the three Tc-rich samples reported here and the previous data for bcc ${\mathrm{Mo}}_{0.4}$ ${\mathrm{Tc}}_{0.6}$. The method for extracting $\frac{2\Delta }{k{T}_c}$ values from specific-heat data is discussed, along with possible uncertainties of this method.