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MA: Fachverband Magnetismus

MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena

MA 48.7: Talk

Thursday, March 23, 2017, 11:00–11:15, HSZ 101

Study of Thermally Tunable Coupled Magnetic Vortex Oscillators with Lorentz Transmission Electron Microscopy and Differential Phase Contrast Microscopy — •Johannes Wild, Michael Vogel, Felix Schwarzhuber, Bernhard Zimmermann, Christian Back, and Josef Zweck — Universität Regensburg, Deutschland

Magnetic vortex oscillators are an ideal system to study the dynamics of magnetic systems at very small length scales and over a wide frequency range. Their dynamic behavior shows characteristics known from other fundamental physical systems like the harmonic oscillator and is in many aspects well understood. Here we present a study of coupled vortices with Lorentz Transmission Electron Microscopy (LTEM) and Differential Phase Contrast Microcopy (DPC) at zero magnetic field. We show a novel technique to control the interaction of two or more vortex oscillators by directly influencing their resonance frequencies. The resonance frequencies depend on the saturation magnetization M_s of the magnetic material, in this case permalloy and is highly dependent on the temperature. We use Joule heating to electrically manipulate the resonance frequencies and thus are able to control the coupling between two vortex oscillators. We systematically mapped the frequency response of both oscillators for different temperatures.