Spin wave spectra of 40-nm thick perpendicularly magnetized circular Permalloy dots of 250 nm radius were measured using ferromagnetic resonance technique in 70-80 GHz range at 4.2 K and in 10 GHz at room temperature. The five sharp resonance peaks were observed for both frequency ranges. The resonance fields can be well described by a magneto-exchange dispersion relation, implying that the observed resonances correspond to circular “drumhead” modes with Bessel-function profiles. The relative distances between neighbor peaks for different frequency ranges were almost the same, while the absolute interpeak distances in millimeter range were ∼30% bigger than at 10 GHz, as predicted by the theory.

Magnetodynamical properties of systems of magnetic nanodisks at the microwave range and low temperatures were studied experimentally. Several periodic square arrays of Permalloy nanodisks deposited onto a glass substrate have been studied. The interdisk center-to-center distance in each array was equal to double disk diameter . The magnetoresonance studies were performed at 70-80 GHz frequency band and at the temperature of 4.2 K. The static external magnetic field was applied perpendicularly to the disks array. As a result the magnetoresonance absorption spectra have been obtained, containing both fundamental mode and spin wave modes. A comparative analysis of the results is performed with the X-band results obtained at T = 300K.

The spectra of magnetoelastic vibrations in spin glass are determined in the absence and in the presence of an external magnetic field. Various cases of magnetoacoustic resonance are considered.

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