Contribution of Divacancies to the Magnetic Aftereffect in Nickel

Abstract

This paper presents a theoretical discussion of the results to be expected from magnetic aftereffect measurements on Ni containing a sufficient number of divacancies. Calculations are made of the stabilization energy for 109°−〈001〉 and 180°−〈110〉 Bloch walls, the walls expected to be most mobile at low magnetic fields. The results show features characteristic of the 〈110〉 symmetry of the divacancies that are not shared by centers with 〈100〉 symmetry: (1) The existence of two relaxation modes having different relaxation times and different interaction energies with the magnetization vector, and (2) the nonvanishing of the stabilization force on 109° walls at large Bloch wall displacements.