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MA: Fachverband Magnetismus

MA 17: Magnetic Thin Films I

MA 17.9: Vortrag

Mittwoch, 25. März 2009, 12:15–12:30, HSZ 04

Topological defects and remanent states in antiferromagnetically coupled multilayers with perpendicular anisotropy — •Nikolai S. Kiselev^1,2, U.K. Rößler¹, A.N. Bogdanov¹, and O. Hellwig³ — ¹IFW Dresden — ²Donetsk Institute for Physics and Technology — ³Hitachi GST, San Jose

In antiferromagnetically coupled multilayers with strong perpendicular magnetic anisotropy the antiferromagnetic state may include complex networks of “antiferromagnetic domain walls”. In contrast to bulk antiferromagnets these defects are determined by a close competition between antiferromagnetic interlayer exchange and dipolar coupling [1,2]. Within a phenomenological theory [1,2] we have classified the topological magnetic defects in the antiferromagnetic ground state. Depending on the material parameters and the magnetic history the antiferromagnetic remanent monodomain state may include sharp domain walls, “trapped” strips of ferro and antiferro defect domains within the wall, and various metastable isolated defects formed from remanent domains with internally ferrimagnetic state. The metastable domain wall of the antiferromagnetic monodomain state can acquire a certain width as ferro strips, which exist either in single domain state or split into a system of domains creating "tiger-tail" patterns. We have calculated equilibrium parameters of ferro strips with tiger-tail textures and determined the conditions of their transition into the single domain state.

[1] N.S. Kiselev, U. K. Rößler, A. N. Bogdanov, O. Hellwig Appl. Phys. Lett. 93 132507 (2008). [2] N.S. Kiselev, et al. arXiv: cond-mat/0811.2378.