Momentum–density distribution of magnetic electrons in ferromagnetic nickel

Abstract

Experimental and theoretical investigations have been made for the first time on thethree-dimensional momentum–density distribution of magnetic electrons in ferromagnetic Ni,ρmag(p), which is the difference in the electron momentum–density distribution between majority- andminority-spin electrons. A magnetic Compton-scattering technique is used to determineρmag(p) by applying the direct Fourier-transform method to reconstructρmag(p) from magnetic Compton profiles. The corresponding theoreticalρmag(p) is calculated by the full-potential linearized augmented plane-wave method. Thepresent theory accurately reproduces the overall structures of experimentalρmag(p).There are, however, slight quantitative discrepancies between the experimental and calculated valuesof ρmag(p) around |p| = 0 au and at the positions related to the X-point. The analysis ofρmag(p) for individual bands attributes negativeρmag(p) near the first Brillouinzone boundary (|p|∼1.0 au) to the superposition of highly negative spin-polarized momentum–densityof the first band and highly positive spin-polarized momentum–densityof the sixth band. The positively polarized momentum–density at|p|∼2.2 au is attributed to the d-like fifth band spin polarizations.