Showing papers on "Permittivity published in 1995"
TL;DR: In this article, the authors present a model for predicting dielectric properties of water and some simple mixtures, which is useful in constructing ovens, in selecting packaging materials, and in developing foods.
377 citations
TL;DR: In this article, the electrical and dielectric properties of poly(hydroxyethyl acrylate), PHEA, and hydrogels were studied by means of DE spectroscopy in wide ranges of frequencies (5-2 × 109 Hz), temperatures (173-363 K) and water contents (0.065-0.46, g of water per gram of dry material).
Abstract: The electrical and dielectric properties of poly(hydroxyethyl acrylate), PHEA, hydrogels were studied by means of dielectric relaxation spectroscopy in wide ranges of frequencies (5–2 × 109 Hz), temperatures (173–363 K) and water contents (0.065–0.46, g of water per gram of dry material). The secondary dipolar mechanisms (γ and βsw) and the dc conductivity mechanism were studied in detail by analyzing the dielectric susceptibility data within the complex permittivity formalism, the modulus formalism, and the complex impedance formalism. For both mechanisms molecular mobility was found to increase with increasing temperature or increasing water content (T-f-h superposition principle). The energy parameters and the shape parameters of the response were determined for both mechanisms at several water contents and temperatures. The temperature dependence of dc conductivity was found to change from Vogel-Tamman-Fulcher (VTF) type to Arrhenius type at water contents of ca. 0.30. At water contents lower than about 0.30 the hydrogels are homogeneous whereas at higher water contents a separate water phase appears. In terms of the strong/fragile classification scheme our results suggest that the PHEA hydrogels are fragile systems. ©1995 John Wiley & Sons, Inc.
279 citations
TL;DR: The degradation of dielectric properties of ferroelectric Pb(ZrxTi1−x)O3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated in this paper.
Abstract: The degradation (fatigue) of dielectric properties of ferroelectric Pb(ZrxTi1−x)O3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated. PZT and SrBi2Ta2O9 thin films were fabricated by metalorganic decomposition and pulsed laser deposition, respectively. Samples with electrodes of platinum (Pt) and ruthenium oxide (RuO2) were studied. The interfacial capacitance (if any) at the Pt/PZT, RuO2/PZT, and Pt/SrBi2Ta2O9 interfaces was determined from the thickness dependence of low‐field dielectric permittivity (er) measurements. It was observed that a low er layer existed at the Pt/PZT interface but not at the RuO2/PZT and Pt/SrBi2Ta2O9 interfaces. In the case of Pt/PZT, the capacitance of this interfacial layer decreases with increasing fatigue while the er of the bulk PZT film remains constant. This indicates that fatigue increases the interfacial layer thickness and/or decreases interfacial layer permittivity, but does not change the bulk properties. For the capacitors with RuO2/PZT/RuO2 and Pt/S...
256 citations
TL;DR: It is shown that the dielectric permittivity of a single crystal lead magnoniobate in the zero- field zero-fieldcooled regime depends linearly on both the inverse temperature and the inverse applied field strength.
Abstract: We measured the time dependencies of the dielectric permittivity of a single crystal lead magnoniobate in the zero-field\char21{}cooled regime. The logarithmic decay of the dielectric response was observed in the glassy phase. We measured the time $\ensuremath{\tau}$ from the moment of the field application for the phase transition from the glasslike to the field-induced ferroelectric state to take place, at temperatures below 220 K. The transition is accompanied by the emerging of the even harmonics of the permittivity. It is shown that $\mathrm{ln}\ensuremath{\tau}$ depends linearly on both the inverse temperature and the inverse applied field strength.
228 citations
TL;DR: Transparent glass-ceramics consisting of a cubic crystalline phase with crystallites having diameters between 20 and 40 nm in the composition of 15K2O15Nb2O5 70TeO2 (mol%) have been fabricated.
Abstract: Transparent glass-ceramics consisting of a cubic crystalline phase with crystallites having diameters between 20 and 40 nm in the composition of 15K2O15Nb2O570TeO2 (mol%) have been fabricated. A phase with cubic structure is formed by post-heat-treatment at around 390°C for 1 h and transforms into a stable phase at temperatures above 450°C. The glass-ceramics consisting of a stable crystalline phase are opaque. The transparency of glass-ceramics is attributed to a small particle size (average radius: 10–20 nm) of the cubic crystalline phase. The optical and dielectric properties for the transparent glass-ceramics obtained by heat-treatment at 425°C for 1 h are: refractive index, n = 2.11 ± 0.02; relative permittivity (1 kHz, 300 K), ϵr = 44 ± 1 and third-order non-linear optical susceptibility, χ(3) = 3.3 × 10−13esu. These values are larger than those for the original base glass, i.e. n = 2.02 ± 0.02, ϵr = 28 ± 1 and χ(3) = 0.9 × 10−13esu. Second-harmonic generation is clearly observed in transparent glass-ceramics. These transparent glass-ceramics have a potential as a new type of non-linear optical material.
190 citations
TL;DR: In this article, a series of thin-film bismuth layer structured ferroelectric (BLSF) materials such as SrBi2Ta2O9, SrBiNb2O 9, and SrBi4Ti4O15 were developed using metallo-organic-decomposition (MOD) spin-on coating techniques.
Abstract: We have developed the series of thin-film bismuth layer structured ferroelectric (BLSF) materials such as SrBi2Ta2O9, SrBi2Nb2O9, SrBi4Ti4O15 and their solid solutions using metallo-organic-decomposition (MOD) spin-on coating techniques. We found that SrBi2Ta2O9 is one of the best potential candidate materials for ferroelectric nonvolatile memories. The SrBi2Ta2O9 thin-film capacitor had the remanent polarization (P r+-P r-) of 20 µ C/cm2, coercive field of 35 kV/cm and dielectric constant of 250. SrBi2Ta2O9 thin film on platinum electrode has fatigue-free characteristics for up to 2×1011 cycles without requiring any complicated electrode system such as conductive oxide. Moreover, SrBi2Ta2O9 thin film has many advantages, e.g., high signal/noise ratio of 8 at 1.2 V, low-voltage operation at as low as 1 V, long data-retention, little surface effect, superior imprint properties and low leakage current. We considered that these advantages are due to (1) less space charge and (2) the inherent domain motion.
189 citations
TL;DR: In this article, the infrared complex permittivity functions of three varieties of maghemite, γ-Fe2O3, having different degrees of vacancy ordering, were determined from their IR reflectance spectra, measured at near to normal incidence on pressed powder pellets.
Abstract: The infrared complex permittivity functions of three varieties of maghemite, γ-Fe2O3, having different degrees of vacancy ordering, have been determined from their IR reflectance spectra, measured at near to normal incidence on pressed powder pellets. The optical constants therefrom obtained have been verified by using them in the simulation of the corresponding absorption spectra for KBr-diluted pellets, and these are in excellent agreement with the experimental spectra. All calculations are based on a procedure for the estimation of the effective dielectric function of a mixture, which incorporates percolation features, recently developed by the authors.
160 citations
TL;DR: In this paper, an attempt has been made to find a correlation between ionic parameters of ceramic materials and their complex permittivity at microwave frequencies, using the Fourier transform infrared reflectivity spectra in the 30-4000 cm−1 range.
Abstract: An attempt has been undertaken to find a correlation between ionic parameters of ceramic materials and their complex permittivity at microwave frequencies Ten Ba(B1/2’B1/2‘)O3 complex perovskite compounds (B’=Y3+, In3+, Nd3+, Gd3+; B‘=Nb5+, Ta5+ and B’=Mg2+, Cd2+, B‘=W6+) are compared in order to study the effect of ionic radii, mass, and valence state on dielectric properties Fourier transform infrared reflectivity spectra in the 30–4000 cm−1 range were measured and evaluated by means of Kramers–Kronig analysis and classical oscillator fit The data were extrapolated below the measured frequency range to estimate the intrinsic microwave losses The correlations between loss, permittivity, ionic size, mass, and effective charge and polar‐phonon mode parameters were investigated Ionic size was revealed to be the most important parameter, determining the tolerance factor of the structure packing and through this controlling the phonon frequencies and dampings as well as the extrapolated low‐frequency int
148 citations
TL;DR: In this paper, a dielectric constant of 1300, dissipation factor of 0.03, Curie temperature of 366 °C, remanent polarization of 36 μC/cm2, coercivity of around 30 kV/cm, and breakdown strength of over 1 MV/cm.
Abstract: Ferroelectric lead zirconate titanate thin films of morphotropic phase boundary composition were fabricated through the sol‐gel spin‐on technique to study the thickness dependence of electrical characteristics. At saturation, the films exhibited a dielectric constant of 1300, dissipation factor of 0.03, Curie temperature of 366 °C, remanent polarization of 36 μC/cm2, coercivity of around 30 kV/cm, and dielectric breakdown strength of over 1 MV/cm. The temperature dependence of permittivity showed an anomalous behavior with annealing temperature. The high temperature dielectric behavior of the films were distinguished by smeared and stunted dielectric maximum.
124 citations
TL;DR: In this article, the fabrication of thin films of lead zirconate titanate (PZT) on platinum-buffered silicon substrates by screen printing was reported.
Abstract: This article reports the fabrication of thick films of lead zirconate titanate (PZT) on platinum‐buffered silicon substrates by screen printing. Crack‐free films, up to 12 μm on a single pass, show a dielectric permittivity of 200, tangent losses of 0.05, remanent polarization of 2.5 μC/cm2, and coercive field of 40 kV/cm. The field‐induced longitudinal piezoelectric coefficient d33 at 40 kV/cm dc bias and 4 kV/cm alternating field corresponded to 50 pC/N. The magnitude of the piezoelectric voltage coefficient g33, computed from the strain coefficient and dielectric permittivity, under the same conditions, was found to be 36×10−3 V m/N, higher than that of a poled PZT bulk ceramic in comparison. These results are promising for a broad variety of sensor applications.
122 citations
TL;DR: In this article, a solid solution system of double perovskite La23TiO3 and the GdFeO3-type perovsite CaTiO 3, (1 − x)CaTiO2, xLa23 TiO3, has been prepared to investigate the crystal structure and the dielectric properties.
TL;DR: In this paper, a new group of compounds with composition (Ba5 5 − x Sr x )Nb 4 O 15, having high permittivity and low loss have been prepared and characterised in the microwave frequency region.
TL;DR: In this article, the electrochemical behavior of Ta-TaO x structures was investigated by impedance spectroscopy, and it was shown that the dielectric properties of the structures strongly depend on the thickness of the oxide, d ox, because of the influence of a sub-stoichiometric oxide of TaO in thin layers, in agreement with previous results obtained by XPS measurements.
TL;DR: In this paper, it was shown that the imaginary part of the permittivity in the submillimeter range is mainly of intrinsic origin, while the real part of permittivities decreases linearly with the increasing tolerance factor t < 1 approaching unity.
Abstract: Dielectric spectroscopy in the submillimeter, millimeter, microwave, and radio frequency range has been performed between 300 and 600 K (for some cases below 300 K) on nine Ba(B1/2’B1/2‘)O3 complex perovskite ceramic compounds. The real part of the permittivity e’ decreases linearly with the increasing tolerance factor t<1 approaching unity. It is insensitive to imperfections in the ceramic, such as impurities, vacancies, etc., and entirely determined by polar lattice vibrations. Its temperature dependence is influenced by the presence of a structural phase transition observed in six of the investigated compounds. It is shown that the imaginary part of the permittivity e‘ in the submillimeter range is mainly of intrinsic origin. The e‘(f) dependences were fitted applying a microscopic theory using polar‐phonon parameters that have been determined in the phonon resonance region by infrared reflection spectroscopy (Part I). The theory allows the extrapolation of minimum intrinsic loss due to polar‐phonon co...
TL;DR: In this article, the dielectric properties of reactively sputtered tantalum pentoxide Ta2O5 thin films have been shown to be amorphous and showed good electrical properties.
TL;DR: In situ thin films of (1−x)Pb(Mg1/3Nb2/3)O3-PbTiO3, (PMN•PT) with composition x=0.1,0.3, 0.35, and 0.4, were deposited on MgO(100) substrates by pulsed laser deposition.
Abstract: In situ thin films of (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3, (PMN‐PT), with composition x=0.1, 0.3, 0.35, and 0.4, were deposited on MgO(100) substrates by pulsed laser deposition. The optimum conditions to form (100) oriented PMN‐PT perovskite phase were at substrate temperatures in the range of 535 to 575 °C with an oxygen pressure of 200 mTorr. The Mg content in PMN‐PT films was found to be essential to the formation of perovskite phase. Heterostructures of PMN‐PT/La0.5Sr0.5CoO3 (LSCO) films were prepared on MgO(100) substrates to evaluate the dielectric properties of the films. The dielectric constant of PMN and PMN‐PT films ranged from 1000 to 3800 at 10 kHz measured at room temperature. The highest dielectric constant was obtained from PMN films with 99% perovskite phase.
TL;DR: It is found that only a small variation in polar cluster size can lead to a wide dielectric dispersion covering several frequency decades, and the temperature dependence of the exponent has been determined.
Abstract: Ferroelectric relaxors belong to a class of materials which possess a local polarization until very high temperature and exhibit a wide frequency range dielectric dispersion around and below ${\mathit{T}}_{\mathrm{max}}$, the temperature of the dielectric maximum. By supposing an exponential-type distribution for the volume of the polar microdomains, we have modeled the dielectric behavior of ferroelectric relaxors. From this model, the low-frequency permittivity appears to follow a power law of ${\mathrm{\ensuremath{\omega}}}^{\mathit{n}}$ type with the exponent n inversely proportional to the width of the size distribution. By analyzing experimental data in two typical ferroelectric relaxors with perovskite-type and tungsten bronze-type structures, the temperature dependence of the exponent has been determined. It comes out that the size of nanodomains begins to strongly increase upon cooling through ${\mathit{T}}_{\mathrm{max}}$, giving rise to a peak of the permittivity which does not result from a true phase transition. The peak observed for the imaginary part of the permittivity corresponds to the temperature at which the dispersion of the real part attains maximum. The interval between the largest and smallest cluster sizes has been estimated. It is found that only a small variation in polar cluster size can lead to a wide dielectric dispersion covering several frequency decades.
TL;DR: In this paper, an improved measurement technique to determine the complex dielectric properties of materials has been developed that extends the validity of the conventional cavity perturbation technique for circular cylindrical rod-shaped samples in circular cylinders resonating in TM/sub 0n0/ modes.
Abstract: An improved measurement technique to determine the complex dielectric properties of materials has been developed that extends the validity of the conventional cavity perturbation technique for circular cylindrical rod-shaped samples in circular cylindrical cavities resonating in TM/sub 0n0/ modes. The method is particularly useful for the dielectric characterization of fragile, low-loss materials that are difficult to machine to typically required thin dimensions. The method further allows for multi-frequency measurements using higher-order radial modes and somewhat alleviates the very small cavity dimensions typically required by the conventional perturbation technique at higher microwave frequencies. A validity criterion for the extended method is given. Measurements of the complex permittivity of NaCl single crystals are presented, showing excellent agreement with theory. >
TL;DR: In this paper, the conduction characteristics of sol-gel ferroelectric Pb(Zr0.4Ti0.6)O3 thin-film capacitors were evaluated by evaluation of time-dependent leakage current (I-t ) and current-voltage ( I-V ) characteristics along with the dielectric properties.
Abstract: We studied the electronic conduction characteristics of sol-gel ferroelectric Pb(Zr0.4Ti0.6)O3 thin-film capacitors by evaluation of time-dependent leakage current ( I-t ) and current-voltage ( I-V ) characteristics along with the dielectric properties. We found two regions in the I-V characteristics, which were (1) ohmic-like current with strong decay time dependence below about 800 kV/cm, and (2) the current with strong electric field dependence above about 1 MV/cm. The leakage current in the ohmic region strongly depended upon the measurement conditions including decay time and the current obeyed the power law of DC stressing time. The hysteresis loop shifted toward a negative field after DC stressing which implied the trapping of positive charges near the top surface. The conduction mechanism of current at high field was considered to be the mixture of Schottky emission and Frenkel Poole emission, taking the dynamic dielectric constant into account. The barrier height and trapped level were estimated to be 0.58 eV and 0.5 eV, respectively.
TL;DR: In this article, the resonance frequencies of the dielectric disk for the HEM/sub 11/ mode are computed numerically in the complex frequency plane and the actual resonance frequency and the Q-factor are obtained.
Abstract: Dielectric disk radiators which are excited by a narrow slot in the ground plane of a microstrip line are investigated. The resonance frequencies of the dielectric disk for the HEM/sub 11/ mode are computed numerically in the complex frequency plane. From the later results, the actual resonance frequency and the Q-factor are obtained. The dielectric disk is made of a high dielectric constant ceramic material with /spl epsivsub r/=22. The radiation patterns and reflection coefficients are measured and presented for several slot lengths and dielectric disk dimensions. The radiation patterns are also computed assuming a magnetic current element, which models the slot and excites the HEM/sub 11/ mode. Good agreement is obtained between the computed and measured results. The results presented here also demonstrate the viability of this type of antenna, which has high dielectric constants an efficient radiator provided the proper mode is excited. >
TL;DR: The microwave properties of single crystalline TiO2 (rutile) were investigated in this article, where the high permittivity of 105 and small tanδ in combination with the low microwave losses of high temperature superconductors (HTS) were utilized to construct a miniaturized X-band resonator with a high quality factor.
Abstract: The microwave properties of single crystalline TiO2 (rutile) were investigated. At a frequency of 7.5 GHz the loss tangent tan δ was found to increase from 1.4×10−7 at 4 K to 4×10−6 at 70 K for electric fields parallel to the crystallographic a,b plane. The high permittivity of 105 and the small tanδ in combination with the low microwave losses of high temperature superconductors (HTS) were utilized to construct a miniaturized X‐band resonator with a high quality factor Q. An assembly of two YBa2Cu3O7 films of 8 mm in diameter separated by a rutile cylinder of 2 mm height provides a TE011 resonance at 9.7 GHz with Qs ranging from 6×105 at 10 K to 105 at 70 K. Frequency scaling of the losses in rutile and in the HTS films indicates Qs in excess of 106 at 1.8 GHz using YBa2Cu3O7 films of two inches in diameter. Such resonators are considered to be key elements for high‐power filters in mobile communications.
Abstract: Artificial dielectric superlattices of SrTiO3/BaTiO3 (STO/BTO) have been formed by a pulsed laser ablation technique with in situ monitoring of reflection high-energy electron diffraction (RHEED) oscillation. The superlattices with a stacking periodicity of a few unit cells show higher dielectric constant than that of (Sr0.5Ba0.5)TiO3 films with change of temperature or applied frequency. The tetragonal structures of the superlattices are maintained at temperatures of more than 200° C owing to a large stress at the interfaces between STO and BTO layers.
TL;DR: The results of a recent investigation of the dependence of induced piezoelectric activity on temperature, electric bias field, and frequency and the electrostrictive response in the relaxor ferroelectric lead magnesium niobate-lead titanate ceramics (Pb(Mg1/3Nb2/3)O3)- x(PbTiO3)) at compositions below 30% PT are presented in this article.
Abstract: In this paper, the results of a recent investigation of the dependence of the induced piezoelectric activity on temperature, electric bias field, and frequency and the electrostrictive response in the relaxor ferroelectric lead magnesium niobate-lead titanate ceramics ( (1- x)(Pb(Mg1/3Nb2/3)O3)- x(PbTiO3)) at compositions below 30% PT are presented. It was observed that the electrostrictive strain at temperatures near the dielectric constant maximum T max increases monotonically with increased PT content. For PMN:PT at compositions near 30% PT, the electrostrictive strain under a 10 kV/cm electric field can reach about 0.15% with very little hysteresis. An exceptionally large piezoelectric response with an effective piezoelectric d33 coefficient in the electric field induced state of over 1,800 pC/N could be achieved for selected PMN:PT compositions and electric bias fields.
TL;DR: In this article, a new quaternary superionic conducting glass with different compositions of the dopant salt AgI was prepared by rapid melt quenching, and the frequency dependence of electrical conductivity, σ, complex permittivity and electrical modulus, M ∗, were studied.
TL;DR: In this paper, the authors derived the temperature dependence and the wavelength dispersion of the electro-optic tensor in all the ferroelectric phases from a smaller set of data: the quadratic polarization-optical tensor of the cubic phase, the dielectric permittivity, and the spontaneous polarization.
Abstract: We relate the linear electro‐optic coefficients to the quadratic polarization‐optic and the elasto‐optic tensors by analyzing the dielectric phenomena driven by the spontaneous and induced polarization as well as the mechanical effects given by the deformation of the crystals. We determine the temperature dependence and the wavelength dispersion of the electro‐optic tensor in all the ferroelectric phases from a smaller set of data: the quadratic polarization‐optic tensor of the cubic phase, the dielectric permittivity, and the spontaneous polarization. Under the assumption that the elasto‐optic tensor at constant polarization is constant, the elasto‐optic coefficients at constant electric field in the ferroelectric phases are derived. Numerical evaluations of these coefficients for two perovskite crystals KNbO3 and BaTiO3 are presented. Modifications of the electro‐optic properties in doped crystals, mainly due to a change of the dielectric permittivity, are discussed as well.
TL;DR: In this article, the dielectric constant, e′, loss tangent (tan δ), and a.c. resistivity are measured in the frequency range of 100 Hz to 5 MHz for the series of samples Cdx Cu1−xFe2−yGdyO4 prepared by the ceramic technique.
Abstract: The dielectric constant, e′, loss tangent (tan δ) and a.c. resistivity (ρa.c.) are measured in the frequency range of 100 Hz to 5 MHz for the series of samples Cdx Cu1−xFe2−yGdyO4 prepared by the ceramic technique. The dispersion in e′ for all the values of x and y=0 and 0.1 shows a normal behaviour except for y=0.1 and x=0.4. The lowering of dielectric intensity in substituted ferrites (y=0.1) and fast dispersion of (ρa.c.) with frequency, are explained as due to the reduced number of Fe3+ participating in the polarization process and the hindrances caused by Gd3+ to the polarization process by localizing Fe2+ ions thereby increasing the resistivity and activation energy. The dispersion in tan δ for unsubstituted samples (y=0.0) shows a normal trend while substituted samples (y=0.1) show relaxation behaviour, which is explained by existing theories.
01 Jan 1995
TL;DR: In this article, a solution to Maxwell's equations has been developed for a three-dimensional medium in the form of the convergent Neumann's series function, where the electric conductivity u and the permittivity E were assumed to be complex-valued functions and to allow frequency dispersion.
Abstract: Based on the integral approach, a solution to Maxwell's equations has been developed for a three-dimensional medium in the form of the convergent Neumann's series function. The electric conductivity u and the permittivity E: of the medium were assumed to be complex-valued functions and to allow frequency dispersion. The medium is stimulated by an extrinsic current of an arbitrary configuration. The question of the rate of convergence of the constructed Neumann's series is studied. A constructive estimate has been obtained for the error of the numerical solution.
TL;DR: In this paper, the application of open-ended coaxial sensors for dielectric measurement of finite thickness composite sheets is studied, and expressions for calculation of the complex aperture admittance for two geometries are presented.
Abstract: The application of open-ended coaxial sensors for dielectric measurement of finite thickness composite sheets is studied. Expressions for calculation of the complex aperture admittance for two geometries are presented. These expressions are used to calculate the dielectric constant of infinite half-space as well as finite thickness slabs. A more efficient method of such calculations, using a personal computer, for low to medium loss dielectrics is demonstrated. The question of when a dielectric layer may be considered as infinitely thick is also addressed, and examples are presented. A different calibration technique (compared to the conventional ones) is described and successfully implemented. This calibration technique utilizes a dielectric sheet with known dielectric properties and thickness. Measurements for different airgaps between the open-ended coaxial line and the dielectric sheet are used to perform and enhance the calibration. The results of this calibration technique and several subsequent measurements are presented and discussed. >
TL;DR: In this paper, permittivity measurements were taken from 0.2 to 20 GHz on fresh peaches of three varieties at three stages of maturity during the harvest season to determine whether dielectric properties might be correlated with maturity.
Abstract: Permittivity measurements were taken from 0.2 to 20 GHz on fresh peaches of three varieties at three stages of maturity during the harvest season to determine whether dielectric properties might be correlated with maturity. Other physical properties of the peach tissue, such as density, moisture content, firmness, and total soluble solids content, were also determined. Several indices, based mainly on dielectric constant and loss factor values at 0.2 and 10 GHz, were developed that are related to stage of maturity, but their values were dependent on the variety. Correlations of the permittivity-based maturity indices with tissue firmness and other properties are presented. Further studies, including permittivity measurements at frequencies lower than 0.2 GHz, are needed to determine the practical usefulness of such permittivity-based maturity indices.
TL;DR: It was concluded that the derived large permittivity values did not result from cell nuclei or mitochondria, and it is suggested that they may arise from the combined effects of several cytoplasmic organelles.
Abstract: Electrorotation (ROT) spectra of Friend murine erythroleukaemia DS19 cells were measured in the frequency range 10 kHz-100 MHz as a function of suspension osmolality and cell differentiation treatment with hexamethylene bisacetamide (HMBA). A minimization program was employed to curve-fit the measured spectra using a single-shell dielectric model, allowing the derivation of cellular interior conductivity and permittivity (valid for the frequency range 10-100 MHz) and the cytoplasmic membrane capacitance (its dependence on the cell differentiation state and suspension osmolality having been reported earlier). Following HMBA treatment, DS19 cells exhibited a slight increment in average interior permittivity and a decrement in interior conductivity, although the changes were not statistically significant. For both untreated and HMBA treated samples, the average interior conductivity increased and permittivity decreased with increasing suspension osmolality. Of significance was that the average permittivity of cell interiors was larger than that of pure water. The electrorotation spectra of freshly prepared cell nuclei were measured, and the derived nuclear dielectric parameters were employed in numerical simulations to investigate the effects of nuclei on the ROT spectra of intact cells. Other cellular internal structures such as mitochondria were also analysed using theoretical simulations. It was concluded that the derived large permittivity values did not result from cell nuclei or mitochondria, and, instead, we suggest that they may arise from the combined effects of several cytoplasmic organelles.