Dielectric Loss Measurements Research Articles

Unidirectional growth, improved structural perfection and physical properties of a semi-organic nonlinear optical dichlorobis(L-proline)zinc(II) single crystal

A single crystal of dichlorobis(L-proline)zinc(II) (LPZ) was successfully grown by the Sankaranarayanan-Ramasamy (SR) method and conventional slow evaporation solution technique (SEST). The lattice parameters of the grown LPZ crystal were confirmed by single crystal X-ray diffraction. The morphology of the conventional method grown LPZ crystal was identified. HRXRD analysis indicates that the crystalline perfections of the grown crystals are excellent without having any low angle internal structural grain boundaries. Etch pit density of the conventional and SR method grown LPZ crystals were calculated. Piezoelectric d33 coefficient of the SR method grown crystal were higher than the conventional method grown LPZ crystal. The dielectric constant and loss measurements were made as a function of temperature in the range between 40°C and 140°C. A low value of dielectric loss was observed in the SR method grown crystal. The obtained transparency for the crystals grown by the SR and conventional methods are 71% and 60%, respectively in the entire visible region. Microhardness measurements revealed the mechanical strength of the grown crystal. Second harmonic generation (SHG) measurement indicates that the SHG efficiency of the grown LPZ crystal was equal to that of KDP crystals.

Ferrimagnetism and Ferroelectricity of the Composite Matrix: SrBi<sub>2</sub>Nb<sub>2</sub>O<sub>9</sub>(SBN)<sub>X</sub>-BaFe<sub>12</sub>0<sub>19</sub>(BFO)<sub>100–X</sub>

A study of the dielectric, magnetic and structural properties of composites based on M-type barium hexaferrite BFO (BaFe12O19) and SBN (SrBi2Nb2O9) is presented. The magneto-dielectric matrix composite (SrBi2Nb2O9)x(BaFe12O19)100–x, (x = 0,25,50,75 and 100 wt%) were prepared by using a new procedure based in the solid state method. X-Ray powder diffraction patterns, Raman and Infrared spectroscopy, M?ssbauer spectroscopy and scanning electron microscopy (SEM) were carried out for better understanding of the microstructural, dielectric and magnetic properties. Radiofrequency (RF) dielectric permittivity, dielectric loss measurements and magnetic and electric hysteresis loops properties are also discussed throughout this paper. The hysteresis loops showed that composite samples preserve the ferrimagnetism and ferroelectricity for hexaferrite when SBN is added to the composite (BFO25P), although they become less coercive. In addition, the effects of organic binders group (TEOS, PVA and glycerin) on structural properties were also investigated.

Crystal Growth, Optical and Dielectric Properties of L-Histidine Hydrochloride Monohydrate Nonlinear Optical Single Crystals

Optically transparent and bulk single crystal of l-histidine hydrochloride monohydrate (LHHC) was successfully grown by slow evaporation technique. The cell parameters and the crystallinity of the grown crystal were estimated by the single-crystal. Optical transmittance of the crystal was recorded using the UV–vis–NIR spectrophotometer. The optical band gap and optical constant of the material were determined by using transmission spectrum. The dielectric loss and dielectric constant measurements as a function of frequency and temperature were measured for the grown crystal.

Investigation of Dielectric Losses in Hydrogenated Amorphoussilicon (a-Si:H) thin Films Using Superconducting Microwave Resonators

Abstract The improvement of the coherence times of superconducting qubits depends on the reduction of the dielectric losses in the insulating materials implemented for the device fabrication. These losses depend on the density of spurious dipoles of different nature (two-level systems, TLSs) which couple to phase qubits and, hence, limit their coherence times. Hydrogenated amorphous silicon (a-Si:H), because of its lower loss tangent (tan δ) among conventional dielectrics (a-SiO, a-SiO2, a-SiN x :H), is considered as the best amorphous dielectric for superconducting qubit application. We have developed a reliable method for the direct measurement of dielectric losses in amorphous dielectric thin films using a novel design based on four lumped superconducting LC resonators connected in series without coupling capacitors. The losses are obtained as tan δ = 1/ Q 0, where Q 0 is the intrinsic quality factor of the resonator, measured at 3 dB above the resonance frequency without any fitting procedure. The series type LC resonators with a-Si:H as dielectric were fabricated by the Nb technology. The measurements were done at the conditions of a qubit application (0.5 -10 GHz frequency range and low temperatures). The low values of the loss tangent of a-Si:H (up to 2.5 x 10 −5 at 4.2 K) have required the development of superconducting housing for the resonators in order to eliminate a spurious dependence of tan δ on the microwave power, by reducing losses which were not originated in the dielectric itself. The results of the simulations agree well with the experiments.

Dielectric relaxation and electronic spectroscopy of double potassium yttrium tetraoxophosphate(V) K3Y(PO4)2 doped by neodymium and europium ions

The paper presents the results of our investigation on electric properties of double potassium yttrium tetraoxophosphate(V) doped by lanthanide ions K3Y(1−x)Lnx(PO4)2 (x = 0.01, 0.05, Ln = Eu3+, Nd3+). Electric permittivity and dielectric loss measurements have been performed on polycrystalline samples in the temperature range −50 °C to +120 °C and frequency range 1 kHz–1 MHz by means of HP 4282A impedance meter. The frequency and temperature dependence of electric properties were analyzed by theoretical models of dielectric relaxation in order to obtain information abut molecular dynamic of our solids in external electric field.

Investigating the structure and dielectric properties of ceramic solid solutions of the SrTiO3-BiScO3 system

Ceramic samples of (1 − x)SrTiO3-(x)BiScO3 system with x = 0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 were synthesized. Neither of the end members of this system are ferroelectric materials. X-ray diffraction analysis reveals that at room temperature, the samples with x = 0.2, 0.3, 0.4, and 0.5 consisted of a mixture of two phases: a cubic center-symmetric Pm3m phase and a tetragonal polar P4mm phase. Dielectric permittivity and dielectric losses measurements of these compositions showed anomalies associated with the diffuse phase transition characteristic of ferroelectrics.

Dielectric relaxation in double potassium yttrium orthophosphate K3Y(PO4)2 doped by praseodymium and dysprosium ions

We report the paper presents the results of electric properties of double potassium yttrium orthophosphates doped by lanthanide ions K 3 Y( 1− x ) Ln x (PO 4 ) 2 ( x = 0.01, 0.05, Ln = Pr 3+ , Dy 3+ ). Electric permittivity and dielectric loss measurements have been performed on polycrystalline samples in the temperature range −50–120 °C and frequency range 1 kHz–1 MHz by means of HP 4282A impedance meter. The frequency and temperature dependence of electric properties were analyzed by theoretical models of dielectric relaxation in order to obtain information abut molecular dynamic of our solids in external electric field.

Growth, structural, vibrational, optical, laser and dielectric aspects of l-alanine alaninium nitrate single crystal

Bulk single crystals of l-alanine alaninium nitrate [abbreviated as LAAN], an intriguing material for frequency conversion has been grown from its aqueous solution by both slow solvent evaporation and by slow cooling techniques. The optimized pH value to grow good quality LAAN single crystal was found to be 2.5. The grown crystals were subjected to single crystal X-ray diffraction studies to determine the unit cell dimensions and morphology. Vibrational frequencies of the grown crystals by Fourier transform infrared spectroscopic technique were investigated. Also, the presence of hydrogen and carbon atoms in the grown sample was confirmed using proton and carbon NMR analyses. The dielectric constant and dielectric loss measurements of the as grown crystal at different temperatures and frequencies of the applied field are measured and reported. LAAN has good optical transmission in the entire visible region with cutoff wavelength within the UV region confirms its suitability for device fabrications. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm. Its Laser Damage Threshold (LDT) was measured and also tested by using a Q-switched Nd:YAG laser and the value of LDT of LAAN is 17.76 GW/cm 2 respectively, is found to be better than certain organic and semiorganic materials.

Investigation of BiFe 0.95Mn 0.03Zn 0.02O 3/Bi 3.15Nd 0.85Ti 2.9Zr 0.1O 12 heterostructure thin film fabricated by a chemical solution deposition technique

A BiFe 0.95Mn 0.03Zn 0.02O 3/Bi 3.15Nd 0.85Ti 2.9Zr 0.1O 12 (BFMZ/BNTZ) heterostructure thin film was prepared on Pt/Ti/SiO 2/Si (1 0 0) substrate by a chemical solution deposition (CSD) technique. The structural, magnetic, dielectric properties, and leakage current of the BFMZ/BNTZ heterostructure thin film were thoroughly investigated. The analysis of X-ray diffraction (XRD) demonstrated that the BFMZ/BNTZ heterostructure thin film was of a polycrystalline perovskite structure. A slim magnetic hysteresis (M-H) loop for the BFMZ/BNTZ heterostructure thin film was observed. The dielectric constant together with dielectric loss measurement indicates that the BFMZ/BNTZ thin film exhibit a lossy dielectric with an ε r of 60.5 and a tan δ of 0.392 at a frequency of 1 MHz. In addition, the leakage current density of BFMZ/BNTZ thin film measured at an applied electric field of 50 kV/cm is about 5.65×10 −4 A/cm 2.

Dielectric relaxation in double potassium yttrium orthophosphate K 3Y(PO 4) 2 doped by ytterbium ions

Electric properties were examined in double potassium yttrium orthophosphates K 3Y( 1− x )Yb x (PO 4) 2 ( x = 0.01, 0.05). Electric permittivity and dielectric loss measurements have been performed on polycrystalline samples in the temperature range −50 °C to 120 °C and frequency range 1 kHz–1 MHz by means of HP 4282A impedance meter. The frequency and temperature dependence of electric properties were analyzed by theoretical models of dielectric relaxation in order to obtain information about molecular dynamic of our solids in external electric field.

Analysis of Mesogenic Characteristics of 6-Chloro-benzothiazol-2-yl-(4-hexadecyloxyphenyl) Diazene—A Smectic Liquid Crystal

Measurements of dielectric constant and dielectric loss at various frequencies have been carried out on the title compound for the entire smectic range of temperature. Dielectric strength, distribution parameter, and activation energy as evaluated from the experimental data are reported in the article. To obtain a deeper insight, the intermolecular interaction between a pair of 6CB4HPD molecules has been analyzed using quantum mechanically optimized molecular geometry and electronic structure with the help of the Gaussian 03 program (Gaussian, Inc., Wallingford, CT) along with B3LYP/6-31G** basis sets. An attempt has been made to correlate the molecular structure, relative energy, and configuration of various interacting pairs and the observed experimental findings.

Growth, Optical, Mechanical and Dielectric Properties of Glycine Zinc Chloride NLO Single Crystals

Single crystals of Glycine Zinc Chloride (GZC) were grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction analysis reveals that the crystal belongs to orthorhombic system with the space group Pna21.The optical transmission study reveals the transparency of the crystal in the entire visible region and the cut off wavelength has been found to be 230 nm. The optical band gap is found to be 3.40eV. The transmittance of GZC crystal has been used to calculate the refractive index (n), the extinction coefficient (K) and the real er and imaginary ei components of the dielectric constant. Mechanical studies were carried out on the as grown crystal. Dielectric constant and dielectric loss measurements were carried out at different temperatures and frequencies. Photoconductivity measurements carried out on the grown crystal reveal the negative photoconducting nature.

Synthesis and dielectric characterization of Ba 0.6Sr 0.4TiO 3 ferroelectric ceramics

Ferroelectric ceramics Ba 0.6Sr 0.4TiO 3 (BST 40) were prepared, by solid-state reaction in the temperature range 1210–1450 °C. Maximum values of the ceramic densities were around 94% of their theoretical value. X-ray diffraction techniques (XRD) and scanning electron spectroscopy (SEM) were used to analyze the structure and the surface morphology of ceramics. Rounded, well defined or abnormal granular growth was observed in the SEM images, vs. sintering conditions and purity of the raw materials. In all samples, BST 40 ceramic is the major phase, but there are also present small amounts of secondary phases, as revealed in XRD diffraction patterns. Permittivity and dielectric loss measurements were performed in the temperature range − 150 to + 150 °C, and 150 Hz–5 MHz frequency values. Permittivity values rising from 1200 to 12,500, with increasing sintering temperatures, were recorded. Narrow and well defined transition peaks were noticed at higher sintering temperatures. Curie temperature was around 2 °C, for samples with the mentioned composition. Permittivity and losses vs. frequency show different behavior whether BST ceramics are in polar or non-polar state and with the distance toward phase transition. Microwave measurements performed at room temperature have shown lower values of permittivity, compared with similar data at low frequency, and dielectric losses lower than 1% at 0.7 GHz. The sintering conditions (temperatures, sintering time, etc.) and purity of the raw materials lead to important changes of transition temperatures in the polymorphic diagram, which we have built—for the other Ba1−xSrxTiO3 compositions (x = 0.25–0.90) sintered at 1260 °C for 2 h.

Growth and characterization of LCOB and NdLCOB single crystals for laser applications

This paper reports the successful growth and characterization of LCOB and NdLCOB single crystals for nonlinear optical and laser applications. The crystals were obtained from their respective melts. The iso-structural nature of the crystals is identified from their X-ray diffraction results. The crystalline quality of the LCOB and NdLCOB single crystals was assessed using HRXRD analysis. The lower cutoff wavelength for both the crystals is at 210nm. However, there are sharp absorption peaks in the spectrum of NdLCOB crystal, which are the characteristic absorptions of the neodymium (Nd3+) ion present in the crystal. The functional groups of the crystals were identified and assigned using the FTIR analysis. The dielectric loss measurements on the crystals reveal that the crystal contains minimum defects. The NdLCOB crystal emits at 1064nm as evident from the PL measurements. The results of the specific heat and laser damage threshold studies are also discussed.

Studies on conventional and Sankaranarayanan–Ramasamy (SR) method grown ferroelectric glycine phosphite (GPI) single crystals

Transparent single crystals of glycine phosphite were grown by Sankaranarayanan–Ramasamy (SR) method and conventional slow evaporation solution technique (SEST) which had the sizes of 100 mm in length, 30 mm diameter and 10×11×8 mm 3. The conventional slow evaporation and Sankaranarayanan–Ramasamy method grown glycine phosphite single crystals were characterized using laser damage threshold, chemical etching, Vickers microhardness, UV–vis–NIR and dielectric analysis. The laser damage threshold value was higher in SR method grown GPI crystal as against conventional method grown crystal. The SR method grown GPI has higher hardness and also higher transmittance compared to conventional method grown crystal. The chemical etching and dielectric loss measurements indicate that the crystal grown by SR method has low density of defects and low value of dielectric loss compared to conventional method grown GPI crystal.

Unidirectional growth of organic nonlinear optical l-arginine maleate dihydrate single crystal by Sankaranarayanan–Ramasamy (SR) method and its characterization

Unidirectional organic nonlinear optical l-arginine maleate dihydrate (LAMD) single crystal has been successfully grown by the Sankaranarayanan–Ramasamy (SR) method. The SR as-grown crystal was transparent and the size was 65mm in length and 15mm in diameter. The grown LAMD crystals have been subjected to single crystal X-ray diffraction, high-resolution X-ray diffraction (HRXRD), piezoelectric, dielectrics, UV–vis–NIR, Vickers microhardness and second harmonic generation (SHG) efficiency study and the results were discussed. The lattice parameters of the grown LAMD crystal are confirmed by single crystal X-ray diffraction and the morphology is investigated in the conventional grown LAMD crystal. Crystalline perfection is observed from HRXRD analysis. Piezoelectric charge coefficients of the grown crystal have been determined. The dielectric constant and loss measurement were made as function of temperature in the range between 40 and 140°C. The improved transparency of the grown crystal is investigated by recording UV–vis analysis. Microhardness measurements reveal that the mechanical strength of the SR-grown LAMD crystal is higher than the that of the conventional method grown crystal. SHG measurements indicate that the SHG efficiency of the grown LAMD crystal at a fundamental wavelength of 1064nm is roughly 1.4 times that of KDP.

Optical, crystalline perfection and mechanical studies on unidirectional grown bis(thiourea) cadmium zinc chloride single crystal

Optically transparent and bulk single crystal of bis(thiourea) cadmium zinc chloride was successfully grown by unidirectional crystal growth technique. The quality of the crystal was examined by high-resolution X-ray diffraction analysis. The cell parameters and the crystallinity of the grown crystal were estimated by the single-crystal and powder X-ray diffraction analyses, respectively. Optical transmittance of the crystal was recorded using the UV–vis–NIR spectrophotometer. The optical band gap and optical constant of the material were calculated by using transmission spectrum. Microhardness measurements were made for the grown crystal using Vicker's microhardness tester. The dielectric loss and dielectric constant measurements as a function of frequency and temperature were measured for the grown crystal.

Effect of Samarium Modification on Structural and Dielectric Properties of (PbSm)(ZrSnTi)O3 System

Samples with representative formula Pb(1–1.5x)Smx(Zr0.7Sn0.3)0.938Ti0.062O3 (PSmZST) with x = 0.0, 0.01, 0.02 and 0.04 were synthesized using conventional solid state ceramic route. Dielectric properties were studied as a function of frequency and temperature. Dielectric constant curves show a hump before the paraelectric transition. Dielectric loss measurements show noticeable changes as compare to the unmodified composition. ac conductivity measurements show that conductivity of samples increases with increase of samarium (Sm) content.

Growth and characterization of new semi-organic l-proline strontium chloride monohydrate single crystals

The present communication deals with the synthesis, single crystal growth and characterization of a new nonlinear optical material l-proline strontium chloride monohydrate ( l-PSCM). Single crystals have been grown using the slow solvent evaporation technique. Single crystal XRD analysis confirmed that the crystal belongs to the orthorhombic structure with lattice parameter a=6.6966(3) Å, b=12.4530(5) Å, c=15.2432(5) Å and space group P2 12 12 1. Presence of various functional groups in l-PSCM and protonation of the ions were confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The melting point of the single crystal was found to be 126 °C using DSC. Ultraviolet–visible spectral analyses showed that the crystal has low UV cut-off at 226 nm combined with very good transparency of 90% in a wide range. The optical band gap was estimated to be 5.82 eV. Capacitance and dielectric-loss measurements were carried out at different temperatures in the frequency range 1 kHz–2 MHz. The dielectric constant and loss factor were found to be 21 and 0.03 at 1 kHz at room temperature, respectively. Microhardness mechanical studies show that hardness number ( H v) increases with load for l-PSCM single crystals the by Vickers microhardness method. Second harmonic generation (SHG) efficiency was found to be 0.078 times the value of KDP.

Eigen Q-factor of electromagnetic oscillations of E-type in waveguide junction of plane waveguides with anisotropic dielectric

The electrodynamic and numerical analysis of eigen Q-factor of electromagnetic modes of E-type in waveguide junction of plain waveguides, fulfilled with anisotropic dielectric in depending on a permittivity tensor components and dielectric loss have been carried out in the paper. The recommendations on using of waveguide junctions for measurement of dielectric losses of the materials are given.