Abstract-The paper is devoted to the study of microwave analogue of Tamm states appearing at the boundary of two different periodical chain-like structures in contact. A comparison of numerical and experimental data is provided for periodical chains of quadripoles modelling our system. As it turns out, at the point of contact of two different periodic structures, significant concentration of electromagnetic wave energy takes place. The corresponding concentration of energy is quite similar to those characteristics for Tamm states concentration which takes place at the boundary between two adjacent photonic crystals. We use the term microwave analogue of Tamm states for the considered periodic chain-like structures.

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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.

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Magnetoresonance (in the frequency range 22–80 GHz) and magnetostatic studies of the La1−xSrxMnO3 compound with strontium impurity concentrations x = 0.15; 0.225; 0.3; 0.45; 0.6, performed at room and liquid helium temperatures. A splitting of the electron magnetic resonance curve is detected for x = 0.3, which serves as evidence of mixed magnetic phases. The samples' concentration dependences of saturation magnetization are determined based on the obtained experimental data.

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