Inelastic neutron scattering study ofPr2Co12Fe5

Abstract

Inelastic neutron scattering measurements have been performed on the intermetallic compoundsPr2Co12Fe5 (and Y2Co12Fe5) on the IN4 time-of-flight spectrometer at the Institut Laue-Langevin, Grenoble.The data on the yttrium-based compound have been used to estimate thephonon scattering. A broad peak is detected at 18 meV, whose deducedQ dependence (when only the magnetic contribution is considered) is consistent with the form factor ofPr3+ ions; inthe high-Q region, the same peak displays a clear phononic character. The experimental results areanalysed by a molecular field model including exchange and crystal-field contributions, and thederived value for the exchange parameter is consistent with the trend inferred by studyingPr2Co17 and Pr2Fe17. A possible mechanism for the generation of the large volume magnetostriction, to bechecked by further experiments, is suggested.