Domain Structures In Magnetic Films Research Articles

A mixed domain structure in magnetic films with large anisotropy

Influence of anisotropy on a bending of a magnetic stripe domain wall due to a magnetostatic stray field of a cylindrical magnetic domain (CMD) that is located within the stripe one is under investigation. It is revealed that for a specific set of physical parameters of the domain structure, energy of domain wall bending anisotropy can suppress the bending. An analytical expression for the bending shape is obtained on account of a change of both magnetostatic energy of the configuration and energy of anisotropy of the domain wall.

X 線フーリエ変換ホログラフィー法による磁性薄膜の磁区構造観察

X 線フーリエ変換ホログラフィー法による磁性薄膜の磁区構造観察

Magnetic force microscopy study of domain structures in magnetic films

Magnetic force microscopy is used to investigate two different types of samples: thin metal films and ferrite garnet films. It is pointed out for garnet films that magnetic force microscopy allows us only to judge the domain structure of surface layers. Problems associated with conducting measurements in external magnetic fields, the effect of the magnetic field of the probe on the investigated domain structure, and using magneto-polarized optics in combination with magnetic force microscopy are considered.

Low-field microwave absorption in epitaxial La0.7Sr0.3MnO3films that results from the angle-tuned ferromagnetic resonance in the multidomain state

We studied magnetic-field-induced microwave absorption in 100--200 nm thick La${}_{0.7}$Sr${}_{0.3}$MnO${}_{3}$ films on SrTiO${}_{3}$ substrate and found a low-field absorption with a very peculiar angular dependence: it appears only in the oblique field and is absent both in the parallel and in the perpendicular orientations. We demonstrate that this low-field absorption results from the ferromagnetic resonance in the multidomain state (domain-mode resonance). Its unusual angular dependence arises from the interplay between the parallel component of the magnetic field that drives the film into multidomain state and the perpendicular field component that controls the domain width through its effect on domain-wall energy. The low-field microwave absorption in the multidomain state can be a tool to probe domain structure in magnetic films with in-plane magnetization.

Domain structure in magnetic films with a saturation magnetization higher than the anisotropy field

The domain structure (DS) of yttrium-iron garnet films with uniaxial anisotropy fields higher than ∼120 Oe was found to have a 3D character: there is a stripe domain structure of a certain type in the surface layer and a structure of another type in the film bulk. It was revealed that in the absence of an external magnetic field, the boundaries of both DSs are almost perpendicular, whereas with an increase in an external field applied in the film plane along the boundaries of the interior-volume DS, the boundaries of the surface DS are gradually reoriented along the external field. This phenomenon is theoretically explained on the basis of the micromagnetic model, which describes DS formation in ferrite films.

Thermodynamically stable fractal-like domain structures in magnetic films

A fractal-like structure of the domain boundaries was revealed in “overcritical” uniaxial Permalloy magnetic films. The fractal dimension of domain boundaries at the film surfaces was determined as a function of the film thickness. It is shown that the phase transition between the two possible types of fractal-like structures is accompanied by a jump in fractal dimension.

Induced unidirectional anisotropy and biperiodic stripe domain structures in magnetic films of subcritical thickness

The existence of biperiodic stripe domain structures in the vicinity of the lines of orientational phase transitions has been found experimentally in uniaxial films of magnetic garnets of subcritical thickness. It is shown that unidirectional anisotropy induced by the magnetic field, leading to a decrease in the effective rigidity of domain boundaries, is the reason for the observed effect.

Nonlinear magneto-optical diffraction from periodic domain structures in magnetic films

The nonlinear optical diffraction in magnetic films with a laminar domain structure and Bloch-type domain walls is investigated for both s and p polarization of incident light. It is shown that the contribution of magnetic domains and domain walls to the nonlinear diffraction can be separated by a polarization analysis of the scattered light.

Nonlinear Optical Diffraction from Periodic Domain Structures in Magnetic Films

Nonlinear Optical Diffraction from Periodic Domain Structures in Magnetic Films

Suppression of the domain structure in uniaxial ferromagnetic films with a superconducting coating

Specific models of domain walls are used to investigate conditions for the single-domain state and quasi-single-domain states in structures with magnetic materials having a quality factor higher than one. It is shown that the critical thickness of the magnetic film in a tangentially magnetized system decreases monotonically as the magnetizing field increases from zero to the transition from the collinear to the homogeneous angular phase and then increases monotonically with increasing external field. In a thin isolated magnetic film, the size of the domains increases exponentially with decreasing thickness. This dependence is logarithmic near the transition to the single-domain state for a film coated on two sides and obeys a power law for a film coated on one side. The establishment of a single-domain state and characteristic features in the asymptotic behavior of the domain structure in magnetic films with and without coatings can be attributed to differences in the asymptotic behavior of the field of a single domain wall.

Formation of a honeycomb domain structure in magnetic films

An analysis is made of the possible formation of a honeycomb domain structure directly from a labyrinth structure in uniaxial magnetic films exposed to a series of uniform magnetic field pulses. It is shown that the scenario for the formation of a honeycomb structure depends on the pulse parameters and on the magnitude of the static magnetizing magnetic field.