Broadband ferromagnetic resonance is measured in single crystalline Fe films of varying thickness sandwiched between MgO layers. An exhaustive magnetic characterization of the films (exchange constant, cubic, uniaxial and surface anisotropies) is enabled by the study of the uniform and the first perpendicular standing spin wave modes as a function of applied magnetic field and film thickness. Additional measurements of nonreciprocal spin-wave propagation allow us to separate each of the two interface contributions to the total surface anisotropy. The results are consistent with the model of a quasi-bulk film interior and two magnetically different top and bottom interfaces, a difference ascribed to different oxidation states.

We report unidirectional transmission of micron-wide spin waves beams in a 55 nm thin YIG. We downscaled a chiral coupling technique implementing Ni₈₀Fe₂₀ nanowires arrays with different widths and lattice spacing to study the non-reciprocal transmission of exchange spin waves down to λ ≈ 80 nm. A full spin wave spectroscopy analysis of these high wavevector coupled-modes shows some difficulties to characterize their propagation properties, due to both the non-monotonous field dependence of the coupling efficiency, and also the inhomogeneous stray field from the nanowires.

We propose an experimental method for the unidirectional excitation of spin waves. By structuring Au nanowire arrays within a coplanar waveguide onto a thin yttrium iron garnet (YIG) film, we observe a chiral coupling between the excitation field geometry of the nanowire grating and several well-resolved propagating magnon modes. We report a propagating spin wave spectroscopy study with unprecedented spectral definition, wavelengths down to 130 nm and attenuation lengths well above 100 μm over the 20 GHz frequency band. The proposed experiment paves the way for future non-reciprocal magnonic devices.

Ti-Mn substituted Ba(MnTi) $_{x}$ Fe $_{12-x}$ O $_{19}$ hexaferrite randomly-oriented composites were obtained by conventional ceramic synthesis. At zero applied magnetic field, in its polycrystalline powder form, this ferrimagnetic compound exhibits a multi-peak permeability spectrum with two high-frequency resonances that converge under the action of an external magnetic field. We conduct a broad-band FMR characterization of this system under an applied magnetic field between 0 and 2 T, and integrate the results with micromagnetic simulations to investigate the presence of high-frequency resonating magnetic domains contingent upon the sample's microstructure. Simulations show that magnetic domains separated by domain walls upon each magnetic particle are responsible for the multi-peak resonance in Ka band. By combining the simulated spectra with an effective medium theory accounting for the dilution effect of the dielectric matrix, we reproduce the zero-field permeability spectra.

Spintronic THz emitters, consisting of Ta/Co/Pt trilayers patterned into lateral-sized rectangles in the 10 μm range, have been integrated in planar electromagnetic antennas of various types (dipole, bow-tie, and spiral). The antenna dimensions and shapes have been optimized with the help of electromagnetic simulations so as to maximize antenna efficiency in both narrow-band and broadband geometries at/around 1 THz. The THz emission has been studied using a pump–probe free space electro-optic sampling setup, both for single-emitter geometry and for arrays of emitters. The results show an increase in the detected THz signal for all antenna geometries, with enhancement ratios in the range of three to fifteen, depending on the antenna type and frequency range, together with changes in the emission bandwidth consistent with simulated characteristics.