Ferromagnetic and antiferromagnetic spin fluctuations and superconductivity in the hcp-phase of Fe

High purity iron, which transforms into the hcp phase under pressure, has recently been reported to be superconducting in the pressure range 150-300 kBar [1]. The electronic structure and the electron-phonon coupling (lambda(ph)) are calculated for hcp iron at different volumes. A parameter-free theory for calculating the coupling constants lambda(sf) from ferromagnetic (FM) and antiferromagnetic (AFM) spin fluctuations is developed. The calculated lambda(sf) are sufficiently large to explain superconductivity especially from FM fluctuations. The results indicate that superconductivity mediated by spin fluctuations is more likely than from electron-phonon interaction. (C) 2002 Published by Elsevier Science B.V.