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MA: Fachverband Magnetismus

MA 45: Magnonics I

MA 45.6: Vortrag

Donnerstag, 19. März 2020, 11:00–11:15, HSZ 401

Frequency multiplication effects in thin ferromagnetic layers detected by diamond nitrogen-vacancy center microscopy — •Chris Körner, Rouven Dreyer, Niklas Liebing, and Georg Woltersdorf — Martin Luther University Halle-Wittenberg, 06120 Halle, Germany

In thin ferromagnetic layers inhomogeneous magnetic properties can lead to frequency multiplication effects generating high harmonics of the rf driving field close to ferromagnetic resonance. Scanning time-resolved Kerr microscopy is employed to spatially resolve those high harmonics as well as parametric excitations [1]. Since the spatial frequency of the magnetic response increases at higher harmonics, the diffraction limited resolution of the microscope leads to an averaging of the Kerr response within the laser spot. Hence, a more local probing technique is required to resolve magnetization dynamics. Because of their extremely small size and strong response to magnetic fields, Nitrogen-vacancy defect centers in diamond offer an ideal method to detect fields locally. The optical detection of magnetic resonance (ODMR) is a double-resonant technique to locally probe magnetic fields with the help of those defect centers [2]. It allows for the detection of up to the 25th harmonic of the rf excitation frequency generated by the precessing magnetic moments in a Permalloy film at low magnetic bias fields as well as parametric excitations at large driving amplitudes.

[1] R. Dreyer et al. ArXiv:1803.04943 (2018)

[2] C. S. Wolfe et al. ArXiv 1512.05418v2 (2016)