Ferromagnetic Resonance with Magnetic Phase Selectivity by Means of Resonant Elastic X-Ray Scattering on a Chiral Magnet

Abstract

Cubic chiral magnets, such as Cu 2 OSeO 3 , exhibit a variety of non-collinear spin textures, including a trigonal lattice of spin whirls, so-called skyrmions. Using magnetic resonant elastic x-ray scattering (REXS) on a crystalline Bragg peak and its magnetic satellites while exciting the sample with magnetic fields at GHz frequencies, we probe the ferromagnetic resonance modes of these spin textures by means of the scattered intensity. Most notably, the three eigenmodes of the skyrmion lattice are detected with large sensitivity. As this novel technique, which we label REXS-FMR, is carried out at distinct positions in reciprocal space, it allows to distinguish contributions originating from different magnetic states, providing information on the precise character, weight and mode mixing as a prerequisite of tailored excitations for applications. arXiv:1909.08293v2 [cond-mat.mtrl-sci]

Skyrmion Qubits: A New Class of Quantum Logic Elements Based on Nanoscale Magnetization

“…Experimental observation of skyrmion helicity is possible using nitrogen-vacancy (NV) magnetometry [50], allowing for a detector-single qubit coupling control by varying the NV sensor distance from the skyrmion. Resonant elastic x-ray scattering [51] techniques provide a direct observation of skyrmion helicity, and when combined with ferromagnetic resonance measurements [52] can offer a promising single-qubit readout method. Finally, coupling a skyrmion to a magnetic force microscopy resonator allows the detection of magnetic states, which appear as resonance frequency shift signals [53].…”

Dynamic Excitations of Chiral Magnetic Textures

“…An alternative technique for the detection of resonant skyrmion dynamics has been established by Pöllath et al in a recent article. 113 The technique is termed resonant elastic x-ray scattering ferromagnetic resonance (REXS-FMR) and combines the microwave excitation of dynamic modes by means of a coplanar waveguide with the detection of the scattered intensity in REXS measurements. As a proof of principle, the authors successfully identified the skyrmion resonance modes as well as other excitations in the field-polarized and helimagnetic phases of the chiral magnet Cu 2 OSeO 3 .…”

Microwave spectroscopy of the low-temperature skyrmion state in Cu2OSeO3

“…When ignoring the field cycling for a moment, the microwave spectrum reminds of the well-established universal spectrum of the cubic chiral magnet [32,33,[46][47][48], although it is more complex due to the presence of the tilted conical state and the LTS. Under decreasing magnetic field (left to right), a change of slope in the Kittel mode marks the onset of the tilted conical state.…”