The effect of confinement between mica and graphene on the structure and dynamics of alcohol-water mixtures has been studied in situ and in real time at the molecular level by atomic force microscopy (AFM) at room temperature. AFM images reveal that the adsorbed molecules are segregated into faceted alcohol-rich islands on top of an ice layer on mica, surrounded by a pre-existing multilayer water-rich film. These faceted islands are in direct contact with the graphene surface, revealing a preferred adsorption site. Moreover, alcohol adsorption at low relative humidity (RH) reveals a strong preference of the alcohol molecules for the ordered ice interface. The growth dynamics of the alcohol islands is governed by supersaturation, temperature, the free energy of attachment of molecules to the island edge and two-dimensional (2D) diffusion. The measured diffusion coefficients display a size dependence on the molecular size of the alcohols, and are about 6 orders of magnitude smaller than the bulk diffusion coefficients, demonstrating the effect of confinement on the behavior of the alcohols. These experimental results provide new insights into the behavior of multicomponent fluids in confined geometries, which is of paramount importance in nanofluidics and biology.

We present a comprehensive investigation of propagating spin waves in nanometer-thick yttrium iron garnet (YIG) films. We use broadband spin-wave spectroscopy with integrated coplanar waveguides (CPWs) and microstrip antennas on top of continuous and patterned YIG films to characterize spin waves with wave vectors up to 10 rad/µm. All films are grown by pulsed laser deposition. From spin-wave transmission spectra, parameters such as the Gilbert damping constant, spin-wave dispersion relation, group velocity, relaxation time, and decay length are derived and their dependence on magnetic bias field strength and angle is systematically gauged. For a 40-nm-thick YIG film, we obtain a damping constant of 3.5 × 10 −4 and a maximum decay length of 1.2 mm. Our experiments reveal a strong variation of spin-wave parameters with magnetic bias field and wave vector. Spinwave properties change considerably up to a magnetic bias field of about 30 mT and above a field angle of θH = 20 • , where θH = 0 • corresponds to the Damon-Eshbach configuration.

We report on the manipulation of magnetization by femtosecond laser pulses in a periodic array of cylindrical nickel nanoparticles. By performing experiments at different wavelength, we show that the excitation of collective surface plasmon resonances triggers demagnetization in zero field or magnetic switching in a small perpendicular field. Both magnetic effects are explained by plasmon-induced heating of the nickel nanoparticles to their Curie temperature. Model calculations confirm the strong correlation between the excitation of surface plasmon modes and laser-induced changes in magnetization.Plasmonic nanostructures enable strong local enhancements of the optical field in areas that are substantially smaller than the wavelength of incident light. This capability offers prospects for magnetic recording. In heat-assisted magnetic recording (HAMR), a plasmonic near-field transducer (NFT) reduces the switching field of high-anisotropy materials via local heating. 1-3 The NFT in this application is a noble metal nanostructure that is placed near the recording medium. Excitation of the NFT at the plasmon resonance frequency efficiently transfers optical energy to a nanoscale region, enabling local switching at reduced magnetic field. In the realm of ultrafast all-optical switching (AOS), 4,5 the use of noble metal plasmonic antennas has also been considered. By placing gold antennas on top of a ferrimagnetic TbFeCo film, Liu and co-workers demonstrated the confinement of magnetic switching to sub-100 nm length scales. 6 .Independent from HAMR and AOS, a new discipline combining plasmonics and magnetism has emerged recently. 7,8 Experiments on pure ferromagnetic metals demonstrate that, despite stronger ohmic damping, they also support surface plasmon resonances. [9][10][11] This raises the question if one could nanostructure the magnetic medium itself to trigger magnetic switching via local enhancements of the optical field. To study the effect of plasmon resonances on magnetic switching it is advantageous to consider ferromagnetic nanoparticles of uniform size and shape. In such nanoparticles, plasmon resonances determine the magneto-optical activity via the excitation of two orthogonal electric dipoles. 12 Plasmon resonances in single ferromagnetic nanoparticles are rather broad. Yet, ordering of the particles into a periodic array significantly narrows the spectral response. 13 In this geometry, hybridization between localized surface plasmons and the diffracted orders of the array produces intense surface lattice resonances (SLRs). SLR modes a) sebastiaan.van.dijken@aalto.fi and, thereby, the optical, magneto-optical, and magnetic circular dichroism (MCD) properties of a ferromagnetic nanoparticle array can be tuned by changing the period or symmetry of the lattice 13-15 or the shape of the nanoparticles. 16 These versatile designer tools could thus be exploited to spectrally gauge the significance of the inverse Faraday effect and MCD on all-optical switching in ferromagnetic materials, a topic of intense sc...

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Cover design: These Icelandic basalt columns are created by the cooling and contracting of lava, which causes the rock to crack into geometric shapes in a process called columnar jointing. Photograph taken by Freija Geldof.