Antivortex state in crosslike nanomagnets

Abstract

We report on results of computer micromodelling of anti-vortex states in asymmetrical cross-like ferromagnetic nanostructures and their practical realization. The arrays of cobalt crosses with 1 μm branches, 100 nm widths of the branches and 40 nm thicknesses were fabricated using e-beam lithography and ion etching. Each branch of the cross was tapered at one end and bulbous at the other. The stable formation of anti-vortex magnetic states in these nanostructures during magnetization reversal was demonstrated experimentally using magnetic force microscopy.

Geometry and field dependence of the formation of magnetic antivortices in pound-key-like structures

“…(1) in Ref. 33) in the vicinity of the core but are increasingly influenced by the structure shape farther from the core region, where the spin distribution becomes more like the AV counterpart of a Landau pattern in a square rather than an ideal vortex in a circular structure. The calculated image (Fig.…”

“…[27][28][29] AV's are frequently observed as part of a cross-tie wall 30,31 but there are few experimental reports on the reliable formation and stabilization of isolated AV's that are not coupled to other nearby vortices or AV's. 27,[31][32][33] Strategies that have been tried include the use of infinityshaped structures, 27,28 formation via controlled domain wall nucleation and propagation, for example, in u-shaped structures, 32 and the use of shape anisotropy as a means to selectively reverse certain regions of a patterned structure to assist the AV formation. 33,34 The first strategy improves stability by providing a channel for flux closure but reliable a) formation can be problematic, the second results in reliable formation but the field treatment requires either a vector magnetic field or rotation stage, and the last strategy requires a simple one-component field treatment but is sensitive to the exact geometry.…”

“…27,[31][32][33] Strategies that have been tried include the use of infinityshaped structures, 27,28 formation via controlled domain wall nucleation and propagation, for example, in u-shaped structures, 32 and the use of shape anisotropy as a means to selectively reverse certain regions of a patterned structure to assist the AV formation. 33,34 The first strategy improves stability by providing a channel for flux closure but reliable a) formation can be problematic, the second results in reliable formation but the field treatment requires either a vector magnetic field or rotation stage, and the last strategy requires a simple one-component field treatment but is sensitive to the exact geometry. In order to study the properties of AV's in greater detail, reliable procedures and geometries to create stable, isolated antivortices are necessary.…”

Electrical detection of magnetic states in crossed nanowires using the topological Hall effect

“…Recently, non-uniform and nanometer-scale magnetic structures such as magnetic domain walls, [1][2][3][4][5] magnetic vortices, [6][7][8][9][10][11][12] antivortices, [13][14][15][16] , and skyrmions [17][18][19][20][21] have been attracting increasing attention for use as high-density memory cells for future non-volatile data-storage devices because of their smallness and their magnetic stability at room temperature. The magnetic vortex and antivortex are one of the most fundamental magnetic states, with two degrees of freedom, namely a polarity and a vorticity.…”

Обратимая Электрохимическая Модификация Поверхности Полупроводников Зондом Атомно-Силового Микроскопа

“…В отличие от электронной литографии [3] АСМ литография, обладая сравнимым разрешением (до 10 нм) [4][5][6], оказывает значительно меньшее воздействие на электронные свойства приповерхностной области [7]. Существенным недостатком и электронно-литографи-ческих, и зондовых методов модификации поверхности является необратимость процесса, когда степень воз-действия на поверхность или характерный размер уже сформированных нанообъектов не могут быть изменены или скорректированы в дальнейшем.…”