Measurement of superhigh-frequency dielectric permittivity for paraelectrics (Ba,Sr) TiO3 in a transverse bias field

An improved apparatus for measuring dielectric permittivity in the shf range by the dielectric-resonance method is described. A cylindrical sample is placed at the antinode of a waveguide magnetic field. A measurement-line probe, placed at the minimum of the standing wave, is used to indicate resonance. Dielectric resonances are traversed by varying the sample temperature and dielectric permittivity. Results of measuring temperature dependences of and tan are given for BaTiO₃ ceramics and BaTiO₃ SrTiO₃ solid solutions in the paraelectric phase. The dependences of on a bias electric field perpendicular to the measuring field are found. It is shown that in a transverse bias field decreases though to a smaller extent than in a longitudinal field. It is concluded that the basic mechanism of paraelectric nonlinearity is the saturation of electron-ion polarization.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 9, pp. 20–25, September, 1971.