Bloch Wall Excitation. Application to Nuclear Resonance in a Bloch Wall

Abstract

The excitation spectrum of an assembly of electronic spins in a Bloch wall structure is studied, assuming a uniaxial anisotropy. The spectrum may be divided into two branches; one is a specific wall excitation and does not spread outside the wall, the other one is similar to the spin-wave excitation spectrum in a uniform ferromagnet. These calculations are used to study the properties of the nuclear magnetic resonances in a Bloch wall. The relaxation times are evaluated, taking into account the damping of the motion of the electronic spins and are compared with experimental values. The spin-spin coupling and the variation of the magnetization across the wall is also estimated.