Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 87: Focus Session: Unconventional Spin Structures (organized by MA)

TT 87.5: Topical Talk

Donnerstag, 3. April 2014, 11:45–12:15, BEY 118

Dynamic ordering of vortex cores in interacting mesomagnets — •Valentyn Novosad — Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA

Manipulation of the magnetization is a key problem in applied magnetism. In this talk a novel method of controlling the ground state using two interacting vortices as a model system will be presented. A spin vortex consists of an in-plane and out-of-plane (core) regions of magnetization. Control of an in-plane magnetization has been demonstrated previously, whereas manipulation of the vortex cores remain challenging. In our work this is achieved by driving the system from the linear regime of constant vortex gyrations to the non-linear regime of vortex-core reversals at a fixed excitation frequency of one of the coupled modes. Subsequently reducing the excitation field to the linear regime, stabilizes the system to a polarity combination whose resonant frequency is decoupled from the initialization frequency [2]. The transition of the state from one polarity combination to the other is clearly evident from the contrast in the microwave absorption amplitude obtained by gradually increasing the rf-field to higher magnitudes at the resonant frequency of one of the modes and subsequently decreasing it. The results of this work may benefit future advancement of dynamically controlled spintronic devices, such as magnonic crystals, spin-torque oscillators, and magnetic memories.

[1] S. Jain, et al., Applied Physics Letters, 102, 052401 (2013).

[2] S. Jain et al., Nature Comm., DOI: 10.1038/ncomms2331 (2012).