The magnetic moment distribution around transition element impurities in iron and nickel

Abstract

The spatial distribution of magnetic moment disturbance around fifteen different transition metal impurities in iron (Ti, V, Cr, Mn, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt) and around four such impurities in nickel (V, Cr, Mn and Fe) has been investigated. A neutron scattering technique was employed that gives information on the spherically averaged moment distribution out to large distances from the impurity atom (similar 10 Å). V, Cr, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt produce a small net increase in moment on iron atoms around an impurity site. Those elements that lie to the right of iron in the periodic table, Co, N1, etc., seem to produce a uniformly positive disturbance in the iron matrix while the remaining elements give a positive disturbance which is apparently confined to a region of a radial extent of approximately 5 Å. All the solutes produce a loss of moment relative to pure iron at the impurity atom sites. The impurity atom moments are generally consistent with those measurements that are available for the more concentrated alloys. Around iron impurities in nickel the moment disturbance is effectively confined to the solute atom site. On the other hand vanadium or chromium impurities reduce the magnetic moment on neighbouring nickel atoms very markedly. The latter system is studied over a range of solute concentrations.