Formation and annihilation of edge walls in thin-film Permalloy strips

We have studied the magnetization reversal of a laterally structured film with both, magneto-optical Kerr effect and with polarized neutron scattering in the off-specular regime. The lateral structure consists of 90-nm thick and 1.2-m wide Co 0.7 Fe 0.3 stripes with a grating period of 3 m. Magnetization reversals were measured for different orientations of the sample with respect to the field directions. In addition, Kerr microscopy was used for visualizing the domain state. Due to the high aspect ratio of the individual stripes, the remagnetization process of the stripe array is dominated by a single domain state over most of the field range. For the easy axis direction, a nucleation and domain wall movement is observed at the coercive field. However, for all other orientations of the stripe array the magnetization reversal is dominated by a coherent magnetization rotation up to the coercive field. For the hard axis orientation the coherent rotation is complete. For this particular stripe array, the agreement between results obtained from MOKE and PNS experiments is very good, mainly due to the specific sample design chosen.

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“…Similar dependencies were found in Ref. 33, where the switching process was found to be dominated by edge curling walls.…”

Section: Cos ͑11͒supporting

confidence: 87%

CoFe stripes: Magnetization reversal study by polarized neutron scattering and magneto-optical Kerr effect

et al. 2003

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“…͑x and y are orthogonal in-plane directions.͒ Unintentional edge roughness of a real wire might change the switching characteristics from device to device. 12 Involved and hysteretic spin-wave resonances are expected since they are known to reflect local variations of M ជ ͑x , y͒ and the magnetic history in a sensitive manner. 13,14 A finite slope and surface anisotropy at edges have already been found to reduce significantly the saturation field.…”

Section: Introductionmentioning

confidence: 99%

Internal spin-wave confinement in magnetic nanowires due to zig-zag shaped magnetization

et al. 2008

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We perform broadband spin-wave spectroscopy on thin submicrometer-wide Ni 80 Fe 20 magnetic wires. Intentionally, we apply the in-plane magnetic field under an angle that is a few degrees off with respect to the in-plane hard-axis direction. In an intermediate field regime we find dipole-exchange modes that, as substantiated by micromagnetic simulations, reflect spin waves in intrinsically formed nanometer-wide channels along the wire. Interestingly, this phenomenon is not ruled by the outer boundary conditions at the geometrical edges but by a deterministic zig-zag shaped magnetization configuration that varies on the nanometer scale in the inner part of the wire. In our case the individual channel width is only 65 nm, about a factor of five smaller than the geometrical width of 300 nm. Internal spin-wave guiding becomes possible, resembling the gradedindex approach for optical wave guiding in fibers. This opens new perspectives for spin-wave propagation in magnonic waveguides.

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“…This hinders the flux-closure tendency of the dipole-dipole interaction, resulting in the formation of magnetic surface and/or volume charges which, in turn, produce long-range dipole fields. Contrary to the ellipsoid case, where a uniform magnetization produces a uniform dipole field, the resulting equilibrium is nonuniform [curling of the magnetization close to the edges [9,10], see Fig. 1(a)].…”

mentioning

confidence: 96%

Micromagnetic Phase Transitions and Spin Wave Excitations in a Ferromagnetic Stripe

2003

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Magnetic excitations of micrometer-wide ferromagnetic stripes subjected to a transverse applied field have been measured between 1 and 20 GHz. The complexity of the observed response is attributed to the spatially nonuniform equilibrium spin distribution. This one is modeled analytically and numerically, which allows one to distinguish two micromagnetic phases governing the ground state. The nucleation-related phase transitions are evidenced by soft modes, while the different observed resonances are attributed to spin wave modes localized in the two phases and at their interface.

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Formation and annihilation of edge walls in thin-film Permalloy strips

Cited by 25 publications

References 4 publications

CoFe stripes: Magnetization reversal study by polarized neutron scattering and magneto-optical Kerr effect

CoFe stripes: Magnetization reversal study by polarized neutron scattering and magneto-optical Kerr effect

Internal spin-wave confinement in magnetic nanowires due to zig-zag shaped magnetization

Micromagnetic Phase Transitions and Spin Wave Excitations in a Ferromagnetic Stripe

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