We use electrical detection, in combination with microwave transmission, to investigate both resonant and non-resonant 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 anti-crossing, line width 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 pave the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling. PACS numbers:Coupling between electrodynamics and magnetization dynamics is a subject of cross-disciplinary and longstanding interest.The nuclear magnetic resonance (NMR) community has studied this effect for decades by measuring the radiation damping of NMR [1]. Engineers have routinely utilized this effect for designing microwave [2] and THz devices [3]. In condensed matter physics, such a coupling leads to the magnon polariton [4], which is an elementary excitation characterized by an intrinsic excitation gap between ferromagnetic resonance (FMR) and ferromagnetic antiresonance [5]. Extrinsically, classical coupling of magnetization dynamics with its electrodynamic surrounding causes Faraday induction of both NMR [6] and FMR [7]. From the perspective of quantum physics, resonant spin-photon coupling plays a central role in utilizing quantum information [8].In 2010, a theoretical work of Soykal and Flatté [9] sparked excitement in the community of spintronics for studying the strong field interaction of magnons and microwave photons. Pioneering experiments have been performed at cryogenic temperatures by Huebl et al. [10] and Tabuchi et al. [11] on the ferromagnetic insulator Yttrium iron garnet (YIG) placed on/in a microwave cavity, in which a large normal mode splitting was found in the transmission measurements, indicating large quantumcoherent magnon-photon coupling. In October 2014, an experimental breakthrough was made by Zhang et al.[12], who demonstrated Rabi-oscillations of the coupled magnon-photon system at room temperature. In the same month, an ultrahigh cooperativity of 10 5 between magnon and photon modes was reported [13]. These exciting works reveal just the tip of the iceberg of the new field of cavity spintronics. * Current affiliation: Department of Physics and Astronomy, University of Denver, Colorado, 80208, USA † Electronic address: hu@physics.umanitoba.ca; URL: http://www.physics.umanitoba.ca/∼hu So far, experiments in this emerging field were performed by measuring either the transmission (S 21 ) or reflection coefficient (S 11 ) of the microwave cavity loaded with a YIG sample. The coupling strength was obtained by fitting these S parameters to the microwave input-output formalism with an added self-energy term attributed to the magnon-photon coupling. This sta...

The hydrophobic effect-a rationalization of the insolubility of nonpolar molecules in water-is centrally important to biomolecular recognition. Despite extensive research devoted to the hydrophobic effect, its molecular mechanisms remain controversial, and there are still no reliably predictive models for its role in proteinligand binding. Here we describe a particularly well-defined system of protein and ligands-carbonic anhydrase and a series of structurally homologous heterocyclic aromatic sulfonamides-that we use to characterize hydrophobic interactions thermodynamically and structurally. In binding to this structurally rigid protein, a set of ligands (also defined to be structurally rigid) shows the expected gain in binding free energy as hydrophobic surface area is added. Isothermal titration calorimetry demonstrates that enthalpy determines these increases in binding affinity, and that changes in the heat capacity of binding are negative. X-ray crystallography and molecular dynamics simulations are compatible with the proposal that the differences in binding between the homologous ligands stem from changes in the number and organization of water molecules localized in the active site in the bound complexes, rather than (or perhaps in addition to) release of structured water from the apposed hydrophobic surfaces. These results support the hypothesis that structured water molecules-including both the molecules of water displaced by the ligands and those reorganized upon ligand binding-determine the thermodynamics of binding of these ligands at the active site of the protein. Hydrophobic effects in various contexts have different structural and thermodynamic origins, although all may be manifestations of the differences in characteristics of bulk water and water close to hydrophobic surfaces.physical-organic | entropy | surface water | benzo-extension | hydration T he hydrophobic effect-the energetically favorable association of nonpolar surfaces in an aqueous solution-often dominates the free energy of binding of proteins and ligands (1-5). Frequently, increasing the nonpolar surface area of a ligand decreases its dissociation constant (K d ; i.e., increases the strength of binding) (6), and simultaneously decreases its equilibrium constant for partitioning from a hydrophobic phase to aqueous solution (K P ) (7). Modern, structure-guided, ligand design has relied upon the "lock-and-key" notion of conformal association between the atoms of the ligand and the binding pocket of a protein; the detailed molecular basis for the hydrophobic effect, however, continues to be poorly understood (1-5). This lack of understanding of the hydrophobic effect prevents accurate prediction of the free energy of binding of proteins and ligands.The first, and currently most pervasive, rationale for the hydrophobic effect was based on studies of the thermodynamics of partitioning of nonpolar solutes from hydrophobic phases (i.e., the gas phase or a hydrophobic liquid phase) into water. The thermodynamics of partitioning of solut...

We report dissipative magnon-photon coupling caused by cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity back action 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.

)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 few years. The first issue is the relation and distinction between different mechanisms that give rise to a photovoltage via FMR in composite magnetic structures, and the second is the proper analysis of the FMR line shape, which remains the "Achilles heel" in interpreting experimental results, especially for either studying the spin pumping effect or quantifying the spin Hall angles via the electrically detected FMR.

We describe the practical implementation of a new RP (pH 10 - pH 2) 2D HPLC-ESI/MS scheme for large-scale bottom-up analysis in proteomics. When compared to the common SCX-RP approach, it provides a higher separation efficiency in the first dimension and increases the number of identified peptides/proteins. We also employed the methodology of our sequence-specific retention calculator (SSRCalc) and developed peptide retention prediction algorithms for both LC dimensions. A diverse set of approximately 10,000 tryptic peptides from the soluble protein fraction of whole NK-type cells gave retention time versus hydrophobicity correlations, with R (2) values of 0.95 for pH 10 and 0.945 for pH 2 (formic acid) separation modes. The superior separation efficiency and the ability to use retention prediction to filter out false-positive MS/MS identifications gives promise that this approach will be a method of choice for large-scale proteomics analyses in the future. Finally, the "semi-orthogonal" separation selectivity permits the concatenation of fractions in the first dimension of separation before the final LC-ESI MS step, effectively cutting the analysis time in half, while resulting in a minimal reduction in protein identification.