相关论文: Defect induced polarization and dielectic relaxati…
The dielectric response in relaxor ferroelectrics is analyzed in the framework a model for the polarization dynamics in the presence of polar clusters. We associate the origin of polar clusters with the atoms displaced from their…
Using molecular dynamics simulation, we study dipolar glass in crystals composed of slightly spheroidal, polar particles and spherical, apolar impurities between metal walls. We present physical pictures of ferroelectric glass, which have…
We show that the experimentally observed behavior of thermal conductivity of dielectric glasses over a wide temperature range can be explained by a combination of two scattering processes. The first one comes from the phonon scattering due…
After a strong electric bias field was applied to a glass sample at temperatures in the millikelvin range its AC-dielectric constant increases and then decays logarithmically with time. For the polyester glass mylar we have observed the…
We perform Metropolis Monte Carlo simulations of the behaviour of a film of insulating material containing a distribution of magnetic nanoparticles. We assume that these particles only interact through dipolar forces and we find that their…
Epitaxial thin films of relaxor PbMg1/3Nb2/3O3 and PbSc0.5Nb0.5O3, and ferroelectric PbZr0.65Ti0.35O3, Pb0.955La0.045Zr0.65Ti0.35O3, and Ba0.4Sr0.6TiO3 were prepared, and their dielectric properties were studied in a broad range of the…
In a recent letter [Phys. Rev. Lett. {\bf 75}, 2360 (1996)] we briefly discussed the existence and nature of ferroelectric order in positionally disordered dipolar materials. Here we report further results and give a complete description of…
We propose that acousto-optical coupling of the electric field to strain fields around defects in disordered $^4$He is causing an increase of the dielectric function with decreasing temperature due to the arrested dynamics of defect…
We investigated the dielectric properties of Pb(Fe1/2Nb1/2)1-xTixO3 single crystals below room temperature. Two dielectric anomalies were detected in sample A while only one was detected in sample B in the temperature range 90~300 K. A…
The physical properties of magnetic nanoparticles have been investigated with focus on the influence of dipolar interparticle interaction. For weakly coupled nanoparticles, thermodynamic perturbation theory is employed to derive analytical…
We report the structural, static, and dynamic properties of Cr$_{0.5}$Fe$_{0.5}$Ga by means of powder x-ray diffraction, magnetization, heat capacity, magnetic relaxation, and magnetic memory effect measurements. DC magnetization and AC…
The recent quest for improved functional materials like high permittivity dielectrics and/or multiferroics has triggered an intense wave of research. Many materials have been checked for their dielectric permittivity or their polarization…
The statistical theory of the dipole flexoelectric (FE) polarization in liquid crystals is used to calculate the temperature dependence of order parameters, the elastic constants and the FE coefficients. Two systems with polar wedge-shaped…
The compound, Fe2TiO5 (FTO)is a well-known uniaxial anisotropic spin-glass insulator with two successive glassy freezing temperatures i.e. transverse (TTF= 9K) and longitudinal (TLF= 55 K). In this article, we present the results of…
We present the dielectric and magnetodielectric properties of Pr0.6Ca0.4MnO3 polycrystalline sample. Dielectric permittivity ({\epsilon'}) (and d{\epsilon'}/dT) portrays the charge order and other magnetic transitions observed in the…
The non-exponential character of the structural relaxation is considered one of the hallmarks of the glassy dynamics and in this context, the singular shape observed by dielectric techniques has attracted the attention of the community for…
A new relaxation mechanism is shown to arise from overdamped two-level systems above a critical temperature $T^*\approx 5$ K, thus yielding an explanation for experimental observations in dielectric glasses in the temperature range between…
Ferroelectric materials are characterized by a spontaneous polar distortion. The behavior of such distortions in the presence of free charge is the key to the physics of metallized ferroelectrics in particular, and of structurally-polar…
We investigate the dielectric response in the glass-electret state of two dipolar glass-forming materials. This unusual polar glassy state of matter is produced when a dipolar liquid is supercooled under the influence of a high electric dc…
Dielectric permittivity was studied in ceramics of relaxor ferroelectric bismuth-sodium titanate Na$_{0.5}$Bi$_{0.5}$TiO$_{3}$. The measurements were performed on as sintered and heat treated in vacuum samples. The diffuse dielectric…