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We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling. [ABSTRACT FROM AUTHOR]

This work reviews and examines two particular issues related with the new technique of electrical detection of ferromagnetic resonance (FMR). This powerful technique has been broadly applied for studying magnetization and spin dynamics over the past ten years. The first issue is the relation and distinction between different mechanisms that give rise to a photovoltage via FMR in spintronic devices, and the second is the proper analysis of the FMR line shape, which has become the "Achilles heel" in interpreting experimental results, especially for either studying the spin pumping effect or quantifying spin Hall angles via the electrically detected FMR. [ABSTRACT FROM AUTHOR]

A spin rectification effect due to the nonresonant magnetization motion has been found, which differs from the previously known spin rectification effect caused by the resonant magnetization precession at ferromagnetic resonance. A phase-resolved electrical detection technique has been used to measure the phase lag between the magnetization response and the driving microwave magnetic field, which demonstrates unambiguously the distinction between the resonant and nonresonant rectification effects. [ABSTRACT FROM AUTHOR]

The phase-resolved ferromagnetic resonance spectra has been electrically measured via a spintronic Michelson interferometer, where the nonlinear coupling between the microwave electric field and magnetic field results in time-independent fields and currents. Besides the microwave power the strength of the electrical signal strongly depends on the relative phase of microwave fields at the ferromagnetic material. Therefore, using a ferromagnetic sensor enables a quantification of microwave transmission in both the phase and amplitude, and demonstrates precision and feasibility in the determination of complex dielectric constants in both ideal dielectric materials and strongly absorbing materials. [ABSTRACT FROM AUTHOR]

We report dissipative magnon-photon coupling caused by the cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity backaction that impedes the magnetization dynamics. This effect is revealed in our experiment as level attraction with a coalescence of hybridized magnon-photon modes, which is distinctly different from level repulsion with mode anticrossing caused by coherent magnon-photon coupling. We develop a method to control the interpolation of coherent and dissipative magnon-photon coupling, and observe a matching condition where the two effects cancel. Our work sheds light on the so-far hidden side of magnon-photon coupling, opening a new avenue for controlling and utilizing light-matter interactions. [ABSTRACT FROM AUTHOR]

We experimentally investigate magnon polaritons arising in ferrimagnetic resonance experiments in a microwave cavity with a tunable quality factor. To this end, we simultaneously measure the electrically detected spin pumping signal and the microwave reflection (the ferrimagnetic resonance signal) of a yttrium iron garnet (YIG)/platinum (Pt) bilayer in the microwave cavity. The coupling strength of the fundamental magnetic resonance mode and the cavity is determined from the microwave reflection data. All features of the magnetic resonance spectra predicted by first principle calculations and an input-output formalism agree with our experimental observations. By changing the decay rate of the cavity at constant magnon-photon coupling rate, we experimentally tune in and out of the strong coupling regime and successfully model the corresponding change of the spin pumping signal and microwave reflection. Furthermore, we observe the coupling and spin pumping of several spin wave modes and provide a quantitative analysis of their coupling rates to the cavity. [ABSTRACT FROM AUTHOR]

Using electrical detection of a strongly coupled spin-photon system comprised of a microwave cavity mode and two magnetic samples, we demonstrate the long distance manipulation of spin currents. This distant control is not limited by the spin diffusion length, instead depending on the interplay between the local and global properties of the coupled system, enabling systematic spin current control over large distance scales (several centimeters in this work). This flexibility opens the door to improved spin current generation and manipulation for cavity spintronic devices.

We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.

We define a measure of redundant information based on projections in the space of probability distributions. Redundant information between random variables is information that is shared between those variables. But, in contrast to mutual information, redundant information denotes information that is shared about the outcome of a third variable. Formalizing this concept, and being able to measure it, is required for the non-negative decomposition of mutual information into redundant and synergistic information. Previous attempts to formalize redundant or synergistic information struggle to capture some desired properties. We introduce a new formalism for redundant information and prove that it satisfies all the properties necessary outlined in earlier work, as well as an additional criterion that we propose to be necessary to capture redundancy. We also demonstrate the behavior of this new measure for several examples, compare it to previous measures, and apply it to the decomposition of transfer entropy.