Dynamic Topological 3D Structures in Moving Domain Walls in Permalloy Films of Various Thicknesses

Present paper is a brief review of the information and existing approaches in the study of domain walls in ferroelectric materials. In the framework of the continuum approach the structure of 180° and 90° domain walls was considered. The results of calculation of width and energy of domain walls were compared with those obtained from ab initio calculations and experimental data. Factors conducive to the broadening of domain boundaries are discussed such as profile temperature fluctuation, capture to nearby defects and surface impact. The structure of charged domain walls was considered under the conditions of screening by free carriers. The structure and characteristics of the moving domain wall are discussed: the local effective mass, the top speed and the mobility. The lateral motion of domain walls in the lattice potential relief in the general case creeping mode is investigated. The factors that control the macroscopic movement of domain walls are studied: an effective quasi-elasticity coefficient and nonlocal effective mass associated with involvement in the movement of the elastic medium surrounding wall. Natural frequency of translational oscillations of domain boundaries and the influence of the size effect were estimated. The interaction of domain walls with different types of defects and their effect on the deformation profile and features of the motion of domain walls are considered.

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Magnetic Solitons in the 1-D Antiferromagnetic Chains of Li2Mn0.98Fe0.02F5 and Na2Mn0.98Fe0.02F5

Zeitschrift für Naturforschung A ◽

10.1515/zna-1996-0809 ◽

1996 ◽

Vol 51 (8) ◽

pp. 939-949 ◽

Cited By ~ 2

Author(s):

Ch. Frommen ◽

M. Mangold ◽

J. Pebler

Keyword(s):

Magnetic Susceptibility ◽

Short Range ◽

Domain Walls ◽

Thermal Excitation ◽

Temperature Dependent ◽

Local Anisotropy ◽

Relaxation Effects ◽

Exponential Temperature Dependence ◽

Moving Domain ◽

Ferromagnetic Ordering

Abstract Measurements of the 57Fe Mössbauer effect and magnetic susceptibility have been performed on 57Fe-doped quasi-1-d antiferromagnetic chains of Li2MnF5 and Na2MnF5 as a function of temperature. The Mössbauer spectra, fitted by the Blume-Tjon model, show definite relaxation effects near the Neel temperature, which are attributed to short-range order with temperature-dependent relax-ation times. The soliton model of non-linear excitations was applied. Experimental data confirm the predicted exponential temperature dependence of the thermal excitation of moving domain walls. From the activation energies E2A/k2 as a function of 1-d exchange energies J/k the local anisotropy energy D/k of -3.7(2) K was derived on the basis of sine-Gordon theory. This result is in fair agreement with -3.5(1) K previously derived from magnetic susceptibility measurements. In the light of our results there is some evidence that at low bridging angle ß ≈ 102(5)° a phase-transition from antiferromagnetic to ferromagnetic ordering occurs.

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