Domain Structure In Ferromagnetic Films Research Articles

Strain-mediated electric-field control of multiferroic domain structures in ferromagnetic films

The converse magnetoelectric effect resulting from the electric-field-induced motion of 90° domain walls in a ferromagnetic film coupled to a single-domain ferroelectric substrate is described theoretically. To that end, the volume fractions of 90° domains with differently oriented in-plane magnetizations are calculated as a function of in-plane strains using the dislocation modeling of stress sources in polydomain heterostructures. Being combined with piezoelectric deformations of a ferroelectric substrate in an electric field, this yields magnetoelectric susceptibilities of ferromagnetic-ferroelectric composites. Remarkably, a giant magnetoelectric susceptibility about 4 × 10−5 s/m is predicted for hybrids comprising Co40Fe60 films coupled to the Pb(Zn1/3Nb2/3)O3-6%PbTiO3 single crystal.

Visualization of the domain structure of ferromagnetic films using the magnetochemical effect

Iron film surfaces have been studied after their chemical treatment in a magnetic field. The chemical treatment of a metal leads to the appearance of a relief image that is interpreted as a “photograph” of magnetic scattering fields. The morphology of the relief image formed is shown to correlate with the domain structure of a magnetic film. The magnetochemical effect revealed allows the visualization of the dependence of the scattering field distribution at the sample surface on external magnetic field.

Magneto-elastic coupling and domain structure in ferromagnetic films near the phase transition

The magneto-elastic properties of thin ferromagnetic films near to the phase transition from the state of homogeneous magnetisation to the state of domain structure in the temperature region T<<Tc are considered. The phase transition is caused either by a change of the film thickness or external magnetic field. Formulae describing magnetic, magneto-elastic and elastic susceptibility tensors are derived. The dispersion relation describing the soft mode of coupled magnetic-elastic excitations is obtained.

Domain structure in uniaxial ferromagnets in the vicinity of a continuous phase transition from a paramagnetic phase to a ferromagnetic one

On the basis of the Landau-Ginzburg theory, the phase transition from the paramagnetic phase to the ferromagnetic phase with domain structure in ferromagnetic films with uniaxial anisotropy has been described. Analytic expressions have been obtained which describe the dependence of the period of the domain structure on the thickness of the film and temperature near the temperature of the phase transition. The results that have been obtained are in qualitative agreement with experimental data obtained for films made of the orthoferrites YFeO 3 and Ho 0.5 D y 0.5FeO 3.

The domain structure of ferromagnetic films electrodeposited on rolled copper substrates

Abstract A series of nickel-iron alloy films in the thickness range 200–1500 Å has been prepared by electrodeposition from solutions of salts of the two metals. Rolled electropolished copper foil possessing a cube texture was used as substrate. All the f.c.c. films show an epitaxial crystal structure as in the work of previous authors on Permalloy. The grain structure of the b.c.c. layers is more complex, comprising four possible orientations of (110) crystallites in the foil plane: the grains have diameter 500–1000 Å. A model to account for the mechanism of the growth of this texture is tentatively suggested in an Appendix. Although constituted of very small particles the b.c.c. layers reveal an ordered domain configuration resembling closely that of a single crystal film of iron with a (100) orientation. The structure of the domains and the interaction with inclusions are discussed.