Chirality selection in the vortex state of magnetic nanodisks with a screw dislocation
IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
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Structural defects in magnetic crystalline materials may locally change magnetic properties and can signiﬁcantly inﬂuence the behavior of magnetic nanostructures. E.g., surface-induced Dzyaloshinskii-Moriya interactions can strongly affect vortex structures in magnetic nanodisks causing a chirality selection. Near lattice defects, the spin-orbit interactions induce local antisymmetric Dzyaloshinskii-Moriya exchange and cause effective anisotropies, which can result in spin canting. Broken inversion symmetry near a defect leads to locally chiral exchange. We present a phenomenological approach for dislocation-induced Dzyaloshinskii-Moriya couplings. As an example we investigate effects of a screw dislocation at the center of a magnetic nanodisk with a vortex state. By numerical calculations on vortex proﬁles we analyze equilibrium parameters of the vortex as functions of applied magnetic ﬁeld and the material and geometrical parameters. It is proposed that magnetic nanodisks with defects provide a suitable experimental setting to study induced chirality by spin-orbit effects.
© Owned by the authors, published by EDP Sciences, 2013