F. Heussner

Supercurrent in a room-temperature Bose-Einstein magnon condensate

Studies of supercurrent phenomena, such as superconductivity and superfluidity, are usually restricted to cryogenic temperatures, but evidence suggests that a magnon supercurrent can be excited in a Bose–Einstein magnon condensate at room temperature.

Time- and power-dependent operation of a parametric spin-wave amplifier

We present the experimental observation of the localized amplification of externally excited spin waves in a transversely in-plane magnetized Ni

Phase-to-intensity conversion of magnonic spin currents and application to the design of a majority gate.

_{81}

A switchable spin-wave signal splitter for magnonic networks

Fe

Localized parallel parametric generation of spin waves in a Ni81Fe19 waveguide by spatial variation of the pumping field

_{19}

Parallel parametric amplification of coherently excited propagating spin waves in a microscopic Ni81Fe19 waveguide

magnonic waveguide by means of parallel pumping. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the dependency of the amplification on the applied pumping power and on the delay between the input spin-wave packet and the pumping pulse. We show that there are two different operation regimes: At large pumping powers, the spin-wave packet needs to enter the amplifier before the pumping is switched on in order to be amplified while at low powers the spin-wave packet can arrive at any time during the pumping pulse.We present the experimental observation of the localized amplification of externally excited, propagating spin waves in a transversely in-plane magnetized Ni81Fe19 magnonic waveguide by means of parallel pumping. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the dependency of the amplification on the applied pumping power and on the delay between the input spin-wave packet and the pumping pulse. We show that there are two different operation regimes: At large pumping powers, the spin-wave packet needs to enter the amplifier before the pumping is switched on in order to be amplified while at low powers the spin-wave packet can arrive at any time during the pumping pulse.

Experimental Investigation of the Temperature-Dependent Magnon Density and Its Influence on Studies of Spin-Transfer-Torque-Driven Systems

Magnonic spin currents in the form of spin waves and their quanta, magnons, are a promising candidate for a new generation of wave-based logic devices beyond CMOS, where information is encoded in the phase of travelling spin-wave packets. The direct readout of this phase on a chip is of vital importance to couple magnonic circuits to conventional CMOS electronics. Here, we present the conversion of the spin-wave phase into a spin-wave intensity by local non-adiabatic parallel pumping in a microstructure. This conversion takes place within the spin-wave system itself and the resulting spin-wave intensity can be conveniently transformed into a DC voltage. We also demonstrate how the phase-to-intensity conversion can be used to extract the majority information from an all-magnonic majority gate. This conversion method promises a convenient readout of the magnon phase in future magnon-based devices.

Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films

The influence of an inhomogeneous magnetization distribution on the propagation of caustic-like spin-wave beams in unpatterned magnetic films has been investigated by utilizing micromagnetic simulations. Our study reveals a locally controllable and reconfigurable tractability of the beam directions. This feature is used to design a device combining split and switch functionalities for spin-wave signals on the micrometer scale. A coherent transmission of spin-wave signals through the device is verified. This attests the applicability in magnonic networks where the information is encoded in the phase of the spin waves.

Characterization of spin-transfer-torque effect induced magnetization dynamics driven by short current pulses

We present the experimental observation of localized parallel parametric generation of spin waves in a transversally in-plane magnetized Ni81Fe19 magnonic waveguide. The localization is realized by combining the threshold character of parametric generation with a spatially confined enhancement of the amplifying microwave field. The latter is achieved by modulating the width of the microstrip transmission line which is used to provide the pumping field. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the spatial distribution of the generated spin waves and compare it with numerical calculations of the field distribution along the Ni81Fe19 waveguide. This provides a local spin-wave excitation in transversally in-plane magnetized waveguides for a wide wave-vector range which is not restricted by the size of the generation area.

Frequency-Division Multiplexing in Magnonic Logic Networks Based on Caustic-Like Spin-Wave Beams

We present parallel parametric amplification of coherently excited, propagating spin waves in a microstructured magnonic Ni81Fe19 waveguide. Amplification is achieved by the pumping field generated by a microwave current flowing through a Cu micro-stripline underneath the waveguide. By employing microfocussed Brillouin light scattering spectroscopy, we investigate the spatial decay of the propagating spin waves and their amplification by means of parallel pumping. We analyze the dependence of the intensity of the amplified spin waves on the spin-wave excitation power, pumping power, and pumping duration, revealing the most efficient working point for a noise-free amplification. This paves the way for a frequency selective amplification of spin waves in microstructured magnonic circuits.