Hyperfine Fields at Nonmagnetic Atoms on Various Sites in Ferromagnetic Heusler Alloys

Abstract

AbstractThe hyperfine fields at Fe and Sn, as determined by Mössbauer effect and NMR, in a new Heusler alloy Ru2FeSn, are reported. By comparison with corresponding data in rhodium based Heusler alloys, it is inferred that a preferential R–Sn (R = Ru or Rh) disorder exists in these alloys. The hyperfine field data on Rh atoms occupying different sites in rhodium Heusler alloys helps to narrow the range of the parameter incorporated to account for the preasymptotic behaviour in the Blandin‐Campbell model of the conduction electron polarization. The calculations indicate for the elements of the s–p series occupying D site in traditional Heusler alloys that, if the change in sign of the hyperfine field occurs at the s2–p2 element (the hyperfine fields at s2–p1 and s2–p3 elements on D site being always observed to be negative and positive, respectively), then for s–p elements on (A, C) site, the change in sign will occur at the s2–p1 element and on B site, it will occur at the s2–p2 element but with the phase reversed i.e., the field at s2–p1 and s2–p3 is positive and negative, respectively. These predictions find strong support from recent experimental data in Heusler alloys.