Lattice dynamics ofLaB6studied by ion channeling: La in the Einstein model

The lattice dynamics of ${\mathrm{LaB}}_6$ were studied between 35 and 500 K with use of 0.9-MeV proton channeling. The results of boron were correctly described in the framework of the Debye model, whereas the Einstein model was used to analyze those for lanthanum. The Einstein temperature deduced from the fit was consistent with values provided by other techniques. No evidence for anharmonic potential was found for the lanthanum. Consequently we make the suggestion that the low-temperature specific-heat anomalies of ${\mathrm{LaB}}_6$ could have an electronic origin.