Magnetostatic effect of the change in the shape of 180^{o} domain walls near grain boundaries in plates of triaxial ferromagnets of the Fe-3% Si-alloy type |
Sheiko L. M. ^{1}, Bagriytchuk A. S. ^{}, Murashkinzeva T. N. ^{} |
1. Zaporizhzhe National University (ZNU), Zhukovsky 66, Zaporizhzhe +380612, Ukraine |
Abstract |
Grain boundaries (GBs) exert a substantial effect on the domain structure (DS) and magnetic properties of polycrystalline materials [1-3]. The role of such defects is especially large in the formation of structure and properties of nanomaterials and composites [4,5], in which the relative volumes of grain boundaries and interphase boundaries can exceed 20%. In this work, we report the results of a theoretical investigation into the main features of the spatial distribution of spontaneous magnetization M_{s}(r), the topology of magnetostatic fields H^{m}(r) near GBs, and the results of calculations of the shape z(x) of 180^{o} DWs in plates of triaxial ferromagnets such as silicon iron (~3% Si) with a surface plane (011) in a demagnetized state (at H^{e}=0). It is shown that in the states of thermodynamic equilibrium Bloch domain walls can bend as a consequence of deviations Δθ(x) of the magnetic moments of atoms m_{a} from the <100> easy axis under the effect of magnetic stray fields H^{m} generated by grain boundaries (the μ^{*} - effect inside magnetic domains near grain boundaries). The magnitudes of the effects studied (the deviations Δθ(x) of the M_{s} vectors from the easy axes, the magnitudes of the flexures Δz^{bend} of domain walls, the extensions of the macroscopic zones Δx^{bend} characterized by inhomogeneous magnetization, as well as the maximum values of the strengths H^{m}_{x} of the magnetostatic fields H^{m} near grain boundaries) increase with decreasing magnetocrystalline anisotropy constant and increasing period of the domain structure 2D. [1] J.Goodenough, Phys. Rev. 1954. V.95. № 4. P. 917-932. [2] A.Hubert, R.Schafer, Magnetic Domains: The Analysis of Magnetic Microstructures (Springer, Berlin, 1998. 696 p.). [3] L.Sheiko, Gh.Brekharya, O.Kulyk, JMMM. 2000. V.215-216. P. 86-88. [4] G.Herzer, JMMM. 1996.V.157-158, P.133-136. [5] F.Mazaleyrat, L.K.Varga, JMMM. 2000. V.215-216. P. 253-259. |
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Presentation: poster at E-MRS Fall Meeting 2005, Symposium B, by Sheiko M. Leonid Submitted: 2005-05-16 16:03 Revised: 2009-06-07 00:44 |