Numerical Simulation of Quasistatic and Dynamic Remagnetization Processes with Special Applications to Thin Films and Nanoparticles

Abstract

Theoretical micromagnetics as founded by W. F. Brown (Brown, 1963) is a basically quite simple phenomenology which allows us to evaluate the total magnetic free energy E _tot of any ferromagnetic body if geometry, material parameters and the magnetization configuration of this body are known. In its “minimal” version, micromagnetics takes into account four energy contributions—energy in the external field (Zeeman, energy) E _ext, energy due to the magnetocrystalline anisotropy E _an, the exchange stiffness energy E _exch and the magnetodipolar interaction energy of the magnetic moments of the ferromagnet, known as the stray (or demagnetizing) field energy E _dem:

$$ E_{tot} = E_{ext} + E_{an} + E_{exch} + E_{dem} . $$

(10.1)

The inclusion of other energy terms—like surface anisotropy or magnetoelastic energy—is possible (and in many cases even necessary), but we are not going to consider them here.