G. V. Golubnichaya

Giant radiofrequency magnetoabsorption in La0.5Sr0.5CoO3 cobaltite

Giant radiofrequency magnetoabsorption in La0.5Sr0.5CoO3 polycrystalline lanthanum cobaltite is studied in the temperature interval 77–300 K and 0.5–12.5 MHz frequency range. The specimen’s Curie temperature TC is about 250 K. The magnetoabsorption is found to increase with decreasing frequency, reaching 58% at f = 0.5 MHz near the Curie temperature. The results are satisfactorily explained based on the known physical ideas of high-frequency wave absorption in magnetic materials. The effects of giant magnetoabsorption and rapid variation of the absorption near the Curie temperature can be used in radiofrequency sensors of the magnetic field and temperature.

The effect of gap width between disks on the Q value of a laminar dielectric disk resonator

The influence of the gap width between disks on the Q value and resonance frequency shift of a laminar dielectric disk resonator operating on whispering-gallery modes has been studied. It is established that an increase in the air gap between disks leads to growth in resonance frequency f of the selected mode and can increase the Q value of the laminar dielectric disk resonator as compared to that of an analogous usual (monolithic) disk resonator.

Rarefaction of the spectrum of H-type whispering-gallery modes in a hemispherical dielectric resonator

A dense spectrum of H-type resonance oscillations (whispering-gallery modes) is observed in a hemispherical dielectric resonator excited by a capacitive slit situated on the equatorial metal mirror surface. The spectrum can be significantly rarefied by exciting the WG modes in the resonator by means of distributed coupling to a dielectric waveguide arranged in a certain special position relative to the hemisphere base.

Peculiarities of H-mode oscillation on the dielectric hemisphere form resonator

This work presents new experimental results of H-mode whispering gallery in the hemisphere dielectric resonators. Peculiarity of electromagnetic field structure of H-mode oscillations, which has been experimentally obtained, and excitation of whispering gallery mode oscillations in hemisphere in a form of equatorial belts are presented.