Pust, L. and Bertotti, G. and Tomas, I. and Vértesy, Gábor (1996) Domainwall coercivity in ferromagnetic systems with nonuniform local magnetic field. PHYSICAL REVIEW B CONDENSED MATTER, 54 (17). pp. 1226212271. ISSN 01631829

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Abstract
Domainwall (DW) coercive field, HCW, which characterizes pinning of DW's in soft magnetic materials, decreases strongly with increasing value of gradient, G, of the effective local DWpositionrestoring magnetic field. Particular shapes of the dependence, HCW(G), can be calculated from the mean energy dissipation of the DW moving over the particular profile of the DW pinning field, Hp. In this paper, HCW(G) is calculated from a wallpinning field, Hp, which is expressed as a stochastic function of the DW coordinate, x(DW). The wallpinning field, Hp, is described as a WienerLevy stochastic process modified by two correlation lengths in such a way that Hp is stationary for large DW displacements and dH(p) /dx(DW) is well defined for small DW displacements. The computed HCW(G) is close to a hyperbolic decrease, but it approaches finite values if G>O and it decreases in a much steeper way than alpha 1/G for high values of G, which agrees with the experimental observations. Experimentally, the dependence HCW(G) was measured on closepacked arrays of cylindrical bubble domains in two thin films of magnetic garnets, where the local field gradient, G, was controlled within the range 10(9)10(10) A/m(2) by changing distances between neighboring DW's. The DW coercive field, HCW, extrapolated from the measured values for G>O was close to 80 A/m for both samples, while HCW(G approximate to 10(10) A/m(2)) was several times smaller. Fitting the calculated HCW(G) dependence to the experimental data, we obtained values of the WienerLevy correlation lengths well comparable to the DW width parameters.
Item Type:  Article 

Subjects:  Q Science / természettudomány > QC Physics / fizika Q Science / természettudomány > QC Physics / fizika > QC06 Physics of condensed matter / szilárdtestfizika 
SWORD Depositor:  MTMT SWORD 
Depositing User:  MTMT SWORD 
Date Deposited:  23 Aug 2013 12:34 
Last Modified:  23 Aug 2013 12:34 
URI:  http://real.mtak.hu/id/eprint/6262 
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