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1. Equation (3.13) should read E N = 2 27βε 3 00 ε 3 0 instead of E N = 2 27βε 3 00 . 2. Equation (3.22) should read:3. Sentence after Eq. (3.22) on page #16 should read:"In the limit of small concentration of the dielectric material in the mixture (q 1) and when ε f /ε d 1, the last two terms in the Eq. (3.22) can be neglected and the renormalized electric field E * in Eq. (3.20) become equal to the electric field E 0 ." instead of: "In the limit of small concentration of the dielectric material in the mixture (q 1) and when ε f /ε d 1, the last three terms in the Eq. (3.22) can be neglected and the renormalized electric field E * in Eq. (3.20) become equal to the electric field E 0 ." 4. Equation for the matrix G ts on page #16 should read G ts = 3n t n s − δ ts instead of G ts = 3n + ns − δ ts . 5. Sentence after equation for the matrix G ts on page #16 should read: "where n = ( r − r i )/| r − r i | and δ ts is the Kroneker symbol." instead of: "where n = ( r − r i )/| r − r i | and δ is the Kroneker symbol. Where ϕ and θ are the azimuthal and polar angles of the vector r − r i ."

The dielectric response of ferroelectric-dielectric composites is theoretically addressed. Dielectric permittivity, tunability (relative change of the permittivity driven by dc electric field), and loss tangent are evaluated for various composite models. The analytical results for small dielectric concentration and relative tunability are obtained in terms of the traditional electrostatic consideration. The results for large tunability are obtained numerically. A method is proposed for the evaluation of the tunability and loss at large concentrations of the dielectric. The basic idea of the method is to reformulate the effective medium approach in terms of electrical energies stored and dissipated in the composite. The important practical conclusion of the paper is that, for random ferroelectric-dielectric composite, the addition of small amounts of a linear dielectric into the tunable ferroelectric results in an increase of the tunability of the mixture. The loss tangent of such composites is shown to be virtually unaffected by the addition of moderate amounts of the low-loss dielectric. The experimental data for (Ba,Sr)TiO3 based composites are analyzed in terms of the theory developed and shown to be in a reasonable agreement with the theoretical results.

Effect of stoichiometry on the dielectric properties and soft mode behavior of strained epitaxial SrTiO3 thin films on DyScO3 substrates Appl. Phys. Lett. 102, 082905 (2013); 10.1063/1.4793649 The effect of the top electrode interface on the hysteretic behavior of epitaxial ferroelectric Pb(Zr,Ti)O3 thin films with bottom SrRuO3 electrode J. Appl. Phys. 112, 064116 (2012); 10.1063/1.4754318 Dielectric and ferroelectric properties of strain-relieved epitaxial lead-free KNN-LT-LS ferroelectric thin films on Sr Ti O 3 substratesThe ferroelectric properties of 500 Å thick strained, epitaxial SrTiO 3 films grown on DyScO 3 substrates by reactive molecular-beam epitaxy are reported. Despite the near 1% biaxial tensile strain, the x-ray rocking curve full widths at half maximum in are as narrow as 7 arc sec ͑0.002°͒. The films show a frequency-dependent permittivity maximum near 250 K that is well fit by the Vogel-Fulcher equation. A clear polarization hysteresis is observed below the permittivity maximum, with an in-plane remanent polarization of 10 C/cm 2 at 77 K. The high T max is consistent with the biaxial tensile strain state, while the superimposed relaxor behavior is likely due to defects.

The in-plane and out-of-plane ferroelectric instabilities in compressed (100)-epitaxial SrTiO3 films were examined by infrared reflection spectroscopy. The strongly stiffened in-plane soft mode frequency softened very slowly on cooling. On the other hand, the silent mode appeared at around 150 K, indicating an out-of-plane ferroelectric transition. This behavior points to a split of in-plane and out-of-plane ferroelectric instability temperatures due to the lowered symmetry of the SrTiO3 lattice caused by mechanical misfit strain. Infrared spectroscopy provides a possibility to detect such an effect in the strained epitaxial ferroelectric films.