Effect of electron-phonon interaction on spin susceptibility inA15 compounds

We calculate the effect of electron-phonon interaction on the long-wavelength static spin susceptibility ${\chi }_{\mathrm{sp}}$ in a normal metal for the case when the electronic density of states N(ɛ) cannot be taken as constant within the range of several times the maximum phonon frequency ${\Omega }_{\max (\mathrm{ħ}=1\mathrm{}}$) around the Fermi level. Such a situation may exist in some of the A15 compounds and in other narrow-band systems. It is found that the electron-phonon interaction can affect the temperature (T) dependence in ${\chi }_{\mathrm{sp}\left(\mathrm{T}\right)}$. The effect is dominated by the electron damping at high temperatures which effectively smears the peak in N(ɛ), thereby reducing the value of ${\chi }_{\mathrm{sp}(\mathrm{T}}$) at high T below its zero-temperature value. We conclude that the analysis of the magnetic susceptibility data on A15 materials based on a simple picture of noninteracting band electrons may overestimate the sharpness of the peak in N(ɛ).