M. Weiler: Nanoscale spin waves in magnetic bilayers and chiral magnets

Our ever-increasing demand for computational power is a constant driving force for technological advancement and research of novel schemes for information processing and storage. The fields of spintronics and magnonics encompass the use of the electron spin and its collective excitations (spin waves) in magnetically ordered materials for these purposes. Efficient generation and manipulation of short-wavelength spin waves are key challenges for magnonics, all the more so in view of the recently discovered nanoscale magnetic skyrmions in chiral magnets. These topologically protected magnetic whirls might one day form the basis for our mass data storage devices and are predicted to efficiently interact with nanoscale spin waves.

Here, I will present two important steps towards the realization of nanoscale magnonics in chiral magnets. First, by exploiting the interfacial nature of spin torques in all magnetic bilayers, we experimentally demonstrate the efficient excitation of nanoscale spin waves from a quasi-uniform external microwave magnetic field [1]. Second, we pioneer the spectroscopy of microwave-frequency spin waves in the Dzyaloshinskii-Moriya-exchange regime and demonstrate that the intrinsic periodicity of the spin spiral structure found in chiral magnets forms a natural magnonic crystal [2].

[1] S. Klingler et al., Phys. Rev. Lett. 120, 127201 (2018) [2] M. Weiler et al., Phys. Rev. Lett. 119, 237204 (2017)