Chiral magnetoacoustics

Nonreciprocal microwave devices are key components of communication platforms. Nonreciprocity can arise in chiral systems, where chirality refers to a fixed handedness that is preserved under time reversal. Chiral excitations (quasiparticles) provide opportunities for the realization of miniaturized microwave components with directional properties. In particular, surface acoustic waves that propagate in magnetic media are chiral and can display pronounced nonreciprocal character. Because surface acoustic waves are an established technological platform, hybrid surface acoustic wave/spin wave devices have great application potential. In this mini-review, we introduce the general concept of chiral and nonreciprocal magnetoacoustic waves. We discuss a widely employed phenomenological model based on magnetoelastic coupling and magneto-rotation that quantitatively accounts for many experimental findings and give a brief overview over selected experiments and advances in this emerging research field

Solid-state magnetic traps and lattices

We propose and analyze magnetic traps and lattices for electrons in semiconductors. We provide a general theoretical framework and show that thermally stable traps can be generated by magnetically driving the particle's internal spin transition, akin to optical dipole traps for ultra-cold atoms. Next we discuss in detail periodic arrays of magnetic traps, i.e. magnetic lattices, as a platform for quantum simulation of exotic Hubbard models, with lattice parameters that can be tuned in real time. Our scheme can be readily implemented in state-of-the-art experiments, as we particularize for two specific setups, one based on a superconducting circuit and another one based on surface acoustic waves.Comment: 18 pages, 8 figure

Temperature dependent study of the spin dynamics of coupled Y3_3Fe5_5O12_{12}/Gd3_3Fe5_5O12_{12}/Pt trilayers

In this study, we investigate the dynamic response of a Y$_3$Fe$_5$O$_{12}$ (YIG)/ Gd$_3$Fe$_5$O$_{12}$ (GdIG)/ Pt trilayer system by measurements of the ferromagnetic resonance (FMR) and the pumped spin current detected by the inverse spin Hall effect. This trilayer system offers the unique opportunity to investigate the spin dynamics of the ferrimagnetic GdIG, close to its compensation temperature. We show that our trilayer acts as a highly tunable spin current source. Our experimental results are supported by micro-magnetic simulations. As the detected spin current in the top Pt layer is distinctly dominated by the GdIG layer, this gives the unique opportunity to investigate the excitation and dynamic properties of GdIG while comparing it to the broadband FMR absorption spectrum of the heterostructure