Paraelectric in a Strong High-Frequency Field

A change in the effective permittivity of a ferroelectric film in the paraelectric phase under the action of a strong high-frequency field (nonequilibrium soft mode heating) is considered. It is shown that this effect must be most clearly pronounced far from the resonance (\omega_0 << \omega_sm), rather than for the external field frequency \omega_0 close to the soft mode frequency \omega_sm. The effective permittivity as a function of the high-frequency field amplitude is calculated using the phenomenological approach and within the microscopic theory based on the simple model of a displacement-type ferroelectric.Comment: 3 two-column page

Electromagnon excitations in modulated multiferroics

The phenomenological theory of ferroelectricity in spiral magnets presented in [M. Mostovoy, Phys. Rev. Lett. 96, 067601 (2006)] is generalized to describe consistently states with both uniform and modulated-in-space ferroelectric polarizations. A key point in this description is the symmetric part of the magnetoelectric coupling since, although being irrelevant for the uniform component, it plays an essential role for the non-uniform part of the polarization. We illustrate this importance in generic examples of modulated magnetic systems: longitudinal and transverse spin-density wave states and planar cycloidal phase. We show that even in the cases with no uniform ferroelectricity induced, polarization correlation functions follow to the soft magnetic behavior of the system due to the magnetoelectric effect. Our results can be easily generalized for more complicated types of magnetic ordering, and the applications may concern various natural and artificial systems in condensed matter physics (e.g., magnon properties could be extracted from dynamic dielectric response measurements).Comment: 5 page

Dielectric properties of PbBO₃ perovskites with mixed-valence substitution in the B position

Dielectric properties of PbBO₃ perovskites with mixed-valence substitution in the B position / V. G. Zalesskiĭ, V. V. LemanovThis paper reports on the synthesis of PbBO3 perovskites with mixed-valence substitution in the B position in which the number of ions n in different valence states occupying oxygen octahedra varies from 2 to 6. The dielectric properties of ceramic samples have been studied at frequencies in the range from 12 Hz to 100 kHz and in the temperature interval 77–450 K. The new compounds have been shown to possess relaxor properties. Original Russian Text © V.G. Zalesskiĭ, V.V. Lemanov, 2010, published in Fizika Tverdogo Tela, 2010, Vol. 52, No. 7, pp. 1365–1369

Light reflection from nonlinear optical dielectric film on a bigyrotropic magnetoelectric substrate at angles close to Brewster angles

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Optical Study of the Electronic Structure and Magnetic Ordering in a weak Ferromagnet FeBO3

Contains fulltext : 35265.pdf (publisher's version ) (Open Access