A Question on the Kohn Anomaly and Screening Effects in Pt and Pt Alloys

Phonon dispersion curves of the [110] T1 branch for pure Pt, Pt 90 Fe 10 , Pt 94 Mn 6 , and Pt 87 V 13 alloys were measured to study the Fermi surface effects using neutron inelastic scattering. For pure Pt, the existence of the Kohn anomaly was confirmed. For the other Pt alloys, however, the Kohn anomaly of the [110] T1 phonon branch was strongly suppressed by alloying at less than 10 at. % of 3d transition elements, although the satellite diffuse peaks along the [100] axis have been reported for these alloys in the previous papers as an enhanced screening effect of impurities due to the special shapes of the Fermi surfaces of Pt. A question is raised on the Fermi surface effects in Pt and Pt alloys.