Resonance Microwave Absorption in He II

Microwave (MW) absorption in liquid 4 He is investigated in the frequency range of 40–200 GHz at T = 1.4–2.5 K. “Whispering gallery” waves were generated by a dielectric disk resonator immersed into the liquid. Resonant absorption of MWs was detected at 180.3 GHz, which corresponds to the roton mini...

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Bibliographic Details
Published in:Journal of low temperature physics 2008-02, Vol.150 (3-4), p.160-167
Main Authors: Rybalko, A., Rudavskii, E., Rubets, S., Tikhiy, V., Derkach, V., Tarapov, S.
Format: Article
Language:English
Subjects:
Characterization and Evaluation of Materials
Condensed Matter Physics
Magnetic Materials
Magnetism
Physics
Physics and Astronomy
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Summary:Microwave (MW) absorption in liquid 4 He is investigated in the frequency range of 40–200 GHz at T = 1.4–2.5 K. “Whispering gallery” waves were generated by a dielectric disk resonator immersed into the liquid. Resonant absorption of MWs was detected at 180.3 GHz, which corresponds to the roton minimum of the liquid helium excitation spectrum. The creation of a single roton is possible because of the presence of the resonator wall which absorbs an extra momentum. The resonance frequency is shown to decrease with temperature in excellent agreement with the temperature dependence of the roton gap obtained previously in the neutron scattering experiment. The temperature dependence of the MW absorption data indicates an anomalous behavior near the λ -point and displays an hysteretic character.
ISSN:0022-2291
1573-7357
DOI:10.1007/s10909-007-9529-0