Showing papers on "Temperature coefficient published in 2020"
TL;DR: In this article, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method.
Abstract: In this study, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3 (LBSCA) glass was added as a sintering aid. The results showed that ceramics consisted of CaMgSi2O6 as the main phase. The second phases were CaSiO3 always existing and Li2SiO3 occurring at substitution content x > 0.05. Li+ substitution effectively lowered sintering temperature due to 0.4 wt% LBSCA and contributed to grain densification, and the most homogeneous morphology could be observed at x = 0.05. The effects of relative density, the second phase, and ionic polarizability on dielectric constant (er) were investigated. The quality factor (Q × f) varied with packing fraction that concerned the second phase. Moreover, the temperature coefficient of the resonant frequency (τf) was influenced by MgO6 octahedral distortion and bond valence. Excellent dielectric properties of the CaMg1−xLi2xSi2O6 ceramic was exhibited at x = 0.05 with er = 7.44, Q × f = 41,017 GHz (f = 15.1638 GHz), and τf = −59.3 ppm/°C when sintered at 900 °C. It had a good application prospect in the field of low-temperature co-fired ceramic (LTCC) substrate and devices.
75 citations
TL;DR: In this paper, a microstrip patch antenna was designed and fabricated using cold sintered CaTiO3-K2MoO4 (CTO-KMO) dielectric composites.
63 citations
TL;DR: In this article, the influence of Sb nonstoichiometry on the sintering behavior, microstructure, phase composition along with microwave dielectric performances for Li3Mg2Sb1−xO6 ceramics were studied.
Abstract: The non-stoichiometric Li3Mg2Sb1−xO6 (0.05 ⩽ x ⩽ 0.125) compounds have been prepared via the mixed oxide method. The influences of Sb nonstoichiometry on the sintering behavior, microstructure, phase composition along with microwave dielectric performances for Li3Mg2Sb1−xO6 ceramics were studied. Combined with X-ray diffraction (XRD) and Raman spectra, it was confirmed that phase composition could not be affected by the Sb nonstoichiometry and almost pure phase Li3Mg2SbO6 was formed in all compositions. Appropriate Sb-deficiency in Li3Mg2SbO6 not only lowered its sintering temperature but also remarkably improved its Q×f value. In particular, non-stoichiometric Li3Mg2Sb0.9O6 ceramics sintered at 1250 °C/5 h owned seldom low dielectric constant er = 10.8, near-zero resonant frequency temperature coefficient τf = −8.0 ppm/°C, and high quality factor Q×f = 86,300 GHz (at 10.4 GHz). This study provides an alternative approach to ameliorate its dielectric performances for Li3Mg2SbO6-based compounds through defect-engineering.
59 citations
TL;DR: In this article, phase formation, crystal structure and dielectric properties of NaCa4V5O17 ceramics fabricated via a solid state reaction route at relatively low temperatures (780-860 °C) were investigated.
Abstract: Phase formation, crystal structure and dielectric properties of NaCa4V5O17 ceramics fabricated via a solid state reaction route at relatively low temperatures (780–860 °C) were investigated. NaCa4V5O17 crystallizes in a triclinic structure. Dielectric properties were measured based on the Hakki-Coleman post resonator method at microwave frequency. Specially, a specimen sintered at 840 °C demonstrated balanced dielectric properties with a permittivity er = 9.72, a quality factor Q×f = 51,000 GHz, and a temperature coefficient of resonance frequency τf = −84 ppm/°C. NaCa4V5O17 ceramics showed excellent chemical compatibility with Ag metal electrodes. Besides, the thermal stability of resonance frequency was effectively adjusted through formation of composite ceramics between NaCa4V5O17 and TiO2 and a near-zero τf ˜ 1.3 ppm/°C accompanied with er = 14.9 and Q×f = 19,600 GHz was achieved when 50% mol TiO2 was added. All the merits render NaCa4V5O17 a potential candidate for multilayer electronic devices.
58 citations
TL;DR: This work presents the design, fabrication, and characterization of temperature sensors using conductive polymer composites patterned on both flexible and stretchable substrates through both drop coating and direct ink writing (DIW), demonstrating the potential for these materials in healthcare monitoring devices.
Abstract: Accurate monitoring of physiological temperatures is important for the diagnosis and tracking of various medical conditions. This work presents the design, fabrication, and characterization of temperature sensors using conductive polymer composites (CPCs) patterned on both flexible and stretchable substrates through both drop coating and direct ink writing (DIW). These composites were formed using a high melting point biopolymer polyhydroxybutyrate (PHB) as the matrix and the graphenic nanomaterial reduced graphene oxide (rGO) as the nanofiller (from 3 to 12 wt%), resulting in a material that exhibits a temperature-dependent resistivity. At room temperature the composites exhibited electrical percolation behavior. Around the percolation threshold, both the carrier concentration and mobility were found to increase sharply. Sensors were fabricated by drop-coating PHB-rGO composites onto ink-jet printed silver electrodes. The temperature coefficient of resistance was determined to be 0.018 /°C for pressed rGO powders and 0.008 /°C for the 3 wt% samples (the highest responsivity of all composites). Composites were found to have good selectivity to temperature with respect to pressure and moisture. Thermal mapping was demonstrated using 6 × 7 arrays of sensing elements. Stretchable devices with a meandering pattern were fabricated using DIW, demonstrating the potential for these materials in healthcare monitoring devices.
57 citations
TL;DR: In this paper, the Mg1-xNa2xWO4 (0.14) microwave dielectric ceramics were prepared through traditional solid-state reaction and sintered at 875−925°C for 4h.
Abstract: The Mg1-xNa2xWO4 (0 ≤ x ≤ 0.14) microwave dielectric ceramics were prepared through traditional solid-state reaction and sintered at 875−925 °C for 4 h. Compared with pure MgWO4 ceramic, the samples with substituting Na+ for Mg2+ could be sintered at a lower temperature, the quality factor values and the densification of microstructure were obviously improved. Raman spectroscopy proved that the relative permittivity was related to the multiple phases and molecular polarizability. In addition, the distortion of [MgO6] octahedron also changed, resulting in resonance frequency temperature coefficient varied nonlinearly from x = 0 to 0.14. Considering the applications of low temperature co-fired ceramics technology, the Mg1-xNa2xWO4 (x = 0.06) ceramic sintered at 875 °C had the best performance. Not only did it have excellent microwave dielectric properties of e r = 10.474, Q × f = 45,868 GHz, and τ f = −69 ppm /oC, but also presented great chemical compatibility with the commonly used Ag electrode.
52 citations
TL;DR: In this paper, cold-sintered composite ceramics were directly pressed/integrated onto a printed circuit board (PCB) using the Cu metallisation as a ground plane for the design and fabrication of a circularly polarized microstrip patch antenna suitable for satellite navigation systems.
Abstract: Bi2Mo2O9-K2MoO4 (BMO-KMO) composite ceramics with >95% theoretical density were densified by cold sintering at 150 °C. XRD, Raman, back-scattered SEM and EDX spectroscopy indicated that the BMO and KMO phases coexisted in all composites without inter-diffusion and secondary phases. Temperature coefficient of resonant frequency with near-zero value ∼ -1 ppm/°C was acheived for BMO-10%KMO with pemittivity ∼ 31 and quality factor ∼ 3,000 GHz. Cold-sintered composite ceramics were directly pressed/integrated onto a printed circuit board (PCB) using the Cu metallisation as a ground plane for the design and fabrication of a circularly polarized microstrip patch antenna suitable for satellite navigation systems which achieved efficiencies 87% at 1561 MHz (BeiDou) and 88% at 1575 MHz (GPS/Galileo). The low cost, low energy integration of temperature stable, cold sintered ceramics directly onto a PCB represents a step change in substrate fabrication technology for RF devices.
50 citations
TL;DR: In this article, thermal stable Y3MgAl3SibO12-TiO2 microwave composite ceramics were firstly fabricated by the high temperature solid phase reaction method.
47 citations
TL;DR: In this article, BaTiO3/Cu composites, as a class of epsilon-negative materials, are rationally designed to achieve a high thermal conductivity yet maintaining the electrical insulative character.
46 citations
TL;DR: In this paper, a series of nanocomposites composed of graphene and P(VDF-TrFE) have been developed for the manufacturing of ultrasensitive and flexible temperature sensor for the first time.
Abstract: New series of nanocomposites composed of graphene and P(VDF-TrFE) have been developed for the manufacturing of ultrasensitive and flexible temperature sensor for the first time. Monolayer graphene sheets were synthesized via sonochemical approach. This graphene embedded into the P(VDF-TrFE) at various concentrations (0−0.09 wt%). The developed nanocomposites were characterized via SEM, XRD, and FTIR. The P-E hysteresis and pyroelectricity measurements were carried out. The thermal stability was emphasized using TG-TDA measurements. The electrical conductivity was investigated under different temperatures. The activation energy and the positive temperature coefficient of conductivity were determined. The developed nanocomposites were examined as temperature sensor at low temperatures (-20−0 °C) and at high temperatures (0−300 °C). Among all prepared nanocomposites, it was found that the inclusion of 0.05 wt% of graphene in the P(VDF-TrFE) resulted in a highly sensitive temperature sensor along the temperature range from -20 °C to 300 °C with sensitivity of 0.025 °C−1. This sample exhibited fast detection of temperature within 4 s and fast recovery time of 3 s. This nanocomposite exhibited high repeatability, stability and reproducibility. Therefore, the developed nanocomposite may be served as efficient, low price, light weight and ultra-sensitive flexible temperature sensor for daily life use.
42 citations
TL;DR: In this paper, cold sintered temperature-stable composites based on LiMgPO4 (LMP) have been presented for electronic packaging and low temperature co-fired ceramic (LTCC) technology.
Abstract: Cold sintered, Li2MoO4‐based ceramics have recently been touted as candidates for electronic packaging and low temperature co‐fired ceramic (LTCC) technology but MoO3 is an expensive and endangered raw material, not suited for large scale commercialisation Here, we present cold sintered temperature‐stable composites based on LiMgPO4 (LMP) in which the Mo (and Li) concentration has been reduced, thereby significantly decreasing raw material costs Optimum compositions, 05LMP‐01CaTiO3‐04K2MoO4 (LMP‐CTO‐KMO), achieved 97% density at <300 °C and 600 MPa for 60 mins Raman spectroscopy, X‐ray diffraction, scanning electron microscopy and energy dispersive X‐ray mapping confirmed the coexistence of end‐members, LMP, CTO and KMO, with no interdiffusion and parasitic phases Composites exhibited temperature coefficient of resonant frequency ~ –6 ppm/°C, relative permittivity ~ 91 and Q×f values ~ 8,500 GHz, properties suitable for LTCC technology and competitive with commercial incumbents
TL;DR: In this paper, a solid solution was formed in 0.2 ≤ x ≤ 0.95 and all the samples belong to pure scheelite phase with the tetragonal structure.
Abstract: Novel scheelite‐type [Ca0.55(Nd1‐xBix)0.3]MoO4 (0.2 ≤ x ≤ 0.95) ceramics were prepared using the solid‐state reaction method. According to the X‐ray diffraction data, a solid solution was formed in 0.2 ≤ x ≤ 0.95 and all the samples belong to pure scheelite phase with the tetragonal structure. As revealed by Raman spectroscopy, the number of vibrational modes decreased with the increase in x value, which further indicated that Bi3+ ions occupied A‐site of scheelite structure. As the x value increased, the sintering temperature decreased from 740°C to 660°C; the permittivity increased from 12.6 to 20.3; the Qf value first decreased slightly and gradually remained stable. Based on the infrared reflectivity spectrum analysis, the calculated permittivity derived from the fitted data shared the same trend with the measured value. The [Ca0.55(Nd0.05Bi0.95)0.3]MoO4 ceramic sintered at 660 °C attained a near‐zero value temperature coefficient ~τf (−7.1 ppm/°C) and showed excellent microwave dielectric properties with a ɛr ~ 20.3 and a Qf ~ 33 860 GHz, making this system a promising candidate in the ultralow temperature cofired ceramic (ULTCC) technology.
TL;DR: The proposed dual parameter measurement scheme greatly simplifies the system structure and reduces the system cost.
Abstract: A Fabry-Perot (F-P) interferometric fiber-optic cantilever sensor is presented for simultaneous measurement of acoustic pressure and temperature, which are demodulated by a single high-speed spectrometer. The acoustic pressure wave pushes the cantilever to produce periodic deflection, while the temperature deforms the sensor and causes the F-P cavity length to change slowly. The absolute length of the F-P cavity of the fiber-optic cantilever sensor is calculated rapidly by using a spectral demodulation method. The acoustic pressure and temperature are obtained by high-pass filtering and averaging the continuously measured absolute cavity length value, respectively. The experimental results show that the acoustic pressure can be detected with an ultra-high sensitivity of 198.3 nm/Pa at 1 kHz. In addition, an increase in temperature reduces the resonant frequency of the acoustic response and increases the static F-P cavity length. The temperature coefficient of the resonance frequency shift and the temperature response of the sensor are -0.49 Hz/°C and 83 nm/°C, respectively. Furthermore, through temperature compensation, the measurement error of acoustic pressure reaches ± 3%. The proposed dual parameter measurement scheme greatly simplifies the system structure and reduces the system cost.
TL;DR: In this article, a rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors.
Abstract: A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to analyze the phase composition and microstructure The dielectric characteristics of SmAlO3 microwave ceramics, using the as-obtained products as original materials, were also studied Compared with the conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 °C The large-size sheet structure was composed of a number of micro/nano-scale crystallites, which were mostly irregular in shape due to the mutual growth and overlapping shapes of adjacent grains The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 °C for 4 h due to the favorable sintering activity of the as-synthesized powders In addition, desired dielectric properties at microwave frequencies (dielectric constant er = 2022, quality factor Q·f = 74110 GHz, and a temperature coefficient of resonant frequency τf = −746 ppm/°C) were achieved
TL;DR: In this paper, a 20% Ce-substituted Nd-Fe-B hot-deformed magnet with a large coercivity (µ 0Hc) of 1.69 T and a remanent magnetization (1.32 T) was demonstrated.
TL;DR: In this paper, the authors used metal chloride (MoCl5) as air stable dopant and fabricated doped graphene film with well-controlled intercalation structure, which showed record high electrical conductivity of 1.73
TL;DR: In this article, the NdY-Fe-B sintered magnet was developed by effective microstructure modification, which exhibits an excellent thermal stability of coercivity with 15 at.% Nd substituted by Y.
TL;DR: In this article, the same mechanism of quenching of R-lines intensity and shortening of lifetime for 2E of Cr3+ ions was shown to occur in low-temperature fluorescence thermometry.
Abstract: Detailed investigations of the spectroscopic properties of Cr3+ ions in β-Ga2O3: 0.05% Cr3+ single crystals grown by the floating zone technique have been performed in the temperature range 4.5–550 K. The luminescence of Cr3+ ions at low temperatures is due to narrow R-lines (2E → 4A2 transitions) and their vibronic sidebands, whereas the broad intense band (4T2 → 4A2 transition) dominates at temperatures above 200 K. The vibronic sidebands of R-lines with amplitude of less than 5 % of the R1 line at a temperature of 4.5 K cover the region of 700-735 nm. The temperature dependencies of the luminescence intensity and the decay time of Cr3+ ions indicate the same mechanism of quenching of R-lines intensity and shortening of lifetime for 2E of Cr3+ ions. The temperature dependence of the R1-line decay time of β Ga2O3: Cr3+ with maximal temperature coefficient │Δτ/ΔT│ = 0.023 ms/K at 120 K and maximal specific sensivitity │(Δτ/ΔT)τ-1│ = 0.017 K-1 at 160 K indicates an application potential of this phosphor for low-temperature fluorescence thermometry.
TL;DR: In this article, the authors have synthesized SnS (tin sulfide) single crystals using a direct vapour transport technique and the layered type growth mechanism has been observed by a scanning electron microscope (SEM).
TL;DR: The temperature coefficient of resistance (TCR) of thin metal lines is often used for applications in thermometry, bolometers, or thermal accelerometers, which simultaneously require low thermal mass and large TCR.
Abstract: The temperature coefficient of resistance (TCR) of thin metal lines is often used for applications in thermometry, bolometers, or thermal accelerometers. However, metal TCR is much degraded in nanometer-thin films due to strong surface scattering, preventing their use as fast thermal sensors, which simultaneously require low thermal mass and large TCR. In contrast, here we show that the TCR of doped two-dimensional (2D) semiconductors is large (∼0.3% K−1 at 300 K in MoS2 and MoTe2) even at sub-nanometer thickness. This is larger than that of any metals with thicknesses up to ∼35 nm and larger than that of ∼95 nm thick Cu lines (0.25% K−1) at 300 K. At 100 K, the TCR of these 2D materials is doubled, ∼0.6% K−1. Comparison with detailed 2D transport models suggests that the TCR could be further enhanced (up to 0.45% K−1 at 300 K and ∼2.5% K−1 at 100 K) by reducing the density of Coulomb impurities and scattering centers. Such high TCR in atomically thin 2D semiconductors could lead to the design of fast thermal sensors.
TL;DR: In this article, negative temperature coefficient (NTC) ceramics based on CaCu3Ti4-xZrxO12 (0.15) compositions have been successfully synthesized by traditional solid-state method.
TL;DR: Li et al. as mentioned in this paper demonstrated a correlation between macroscopic "dark hole" phenomena and the microwave dielectric properties of LT-LMN ceramics by analysing the valence states of Ti ions and the content of oxygen vacancies using X-ray photoelectron spectra.
TL;DR: In this paper, the correlation between the temperature coefficient (TC) and different photovoltaic parameters for organic hole transport layer (HTL)-free carbon-based perovskite solar cells (c-PSCs) was evaluated under both steady temperature (ST) and transient temperature (TT) conditions.
Abstract: Perovskite solar cells (PSCs) have emerged in a “catfish effect” of other established photovoltaic technologies with the rapid development of high-power conversion efficiency (PCE) and low-cost fabrication. Among various kinds of PSCs, organic hole transport layer (HTL)-free carbon-based PSCs (c-PSCs) have been considered as the most promising devices due to their excellent stability. However, temperature becomes one of the crucial factors in determining the pace of PSC commercialization. Temperature stress at the interface between the perovskite film and the charge transport layer is an essential factor in determining the performance of c-PSCs. This work assesses the correlation between the temperature coefficient (TC) and different photovoltaic parameters for HTL-free c-PSCs. To evaluate different photovoltaic parameters of the c-PSC as a function of temperature, two different testing approaches namely under steady temperature (ST) and transient temperature (TT) conditions have been considered across a wide temperature window (5–75 °C) under 1 Sun 1.5 AM. Here TT testing involves subjecting a single c-PSC to a continuous temperature treatment, whereas ST testing consists of specific temperature treatment of an individual c-PSC. The maximum efficiency achieved at 25 °C for TT testing devices is ∼14.5%, which is ∼11% higher than that of ST testing devices (PCE ∼ 13%). Moreover, the efficiency temperature coefficient (ETC) for ST testing was found to be 3.5 × 10−2 (5 °C ≤ T ≤ 25 °C) and −2.1 × 10−2 (25 °C ≤ T ≤ 75 °C), whereas the ETC values of TT testing devices were +2.5 × 10−2 (5 °C ≤ T ≤ 25 °C) and −1.8 × 10−2 (25 °C ≤ T ≤ 75 °C), respectively. The outcome of temperature stress transmitting through different interfacial layers was further investigated by thermal imaging of TT devices. On the other hand, X-ray diffraction and scanning electron microscopy structural analyses were performed to understand the effect of thermal stress on the overall performance of ST devices. It has been observed that TC values obtained under TT testing conditions are reversible, whereas in the case of ST testing the TC values are irreversible which shows degradation of the device.
TL;DR: In this article, the influence of BCZN content on the microstructure, dielectric, thermal, mechanical properties and moisture absorption of PTFE composites was investigated.
TL;DR: In this paper, the Nd2Fe14B grains were isolated by Nd-Ga-Cu-rich intergranular phases and the average grain size was reduced by approximately 25%.
TL;DR: In this article, a detailed experimental and theoretical study of the effects of vanadium substitution for Fe atom on the structural, magnetic, transport, electronic and mechanical properties of an off-stoichiometric Fe3−xVxGe intermetallic alloy series (0 ≤ x ≤ 1 ) is reported.
TL;DR: In this paper, the AC complex impedance spectroscopy technique was utilized to extract electrical parameters in (PbTiO3)0.03 ceramic in wide ranges of frequencies and temperatures.
Abstract: The AC complex impedance spectroscopy technique was utilized to extract electrical parameters in (PbTiO3)0.97-(LaFeO3)0.03 ceramic in wide ranges of frequencies and temperatures. The sample was prepared by sol-gel process and the single phase was confirmed using x-ray diffraction. The compound exhibits high dielectric constant (er max ~ 6050) for 1 kHz and low dielectric losses (tanδ < 0.1), diffuse phase transition at Curie temperature of 373 °C, and relaxer behavior. Simultaneous analysis of impedance, modulus, and electrical conductivity was performed. Complex impedance plots show semicircular arcs described by an electrical equivalent circuit which was proposed to explain the impedance results. Off-centered semicircular impedance plots show that the sample obeys to a non-Debye relaxation process. The decrease of resistance, with increasing temperature, indicates a negative temperature coefficient of resistance. Both activation energies, calculated from the conductivity 0.588 eV and the relaxation time 0.49 eV, were comparable highlighting that the relaxation process and conductivity have the same origin.
TL;DR: In this paper, a wearable paper-based temperature sensor is fabricated using printing paper and poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) solution.
Abstract: A highly sensitive, flexible, and wearable paper-based temperature sensor is fabricated using printing paper and poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) solution. It exhibits a negative temperature coefficient and is implemented in a new band-like body-attachable thermometer. Compared to the polymer substrate, the use of hydrophilic and flexible paper substrate facilitates significantly superior sensitivity and simple fabrication. The paper sensor is fabricated by depositing PEDOT:PSS onto the paper with an 80 g base weight for 40 s, which is covered with a 50 μm film to protect it from humidity. This is followed by a heat treatment at 150 °C for 10 min. The paper sensor exhibited an electrical conductivity of 0.48 Ωcm−1 at room temperature with a linearity of 99.86 %. Remarkably, its sensitivity is 658.5 Ω/°C, which is 14 times higher than that of sensor with polyimide substrate (46 Ω/°C), for the body temperature range of 30–42 °C. The paper-based temperature sensor is implemented in a body-attachable patch for a wearable thermometer, which is simply connected with a circuit part for signal processing and the results are transferred to a phone via Bluetooth. The proposed inexpensive sensor is potentially useful for a wide range of flexible electronics and healthcare applications.
TL;DR: In this paper, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30 has been synthesized and systematically studied for structure, dielectric and electrical properties.
Abstract: In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30 has been synthesized and systematically studied for structure, dielectric and electrical properties. The formation of the phase of tetragonal tungsten bronze with space group P4bm and the occurrence of oxygen vacancies were verified by the Rietveld refinement using X-ray diffraction data. Scanning electron microscopy (SEM) of Ba5CaTi1.94Zn0.06Nb8O30 ceramic shows high densification, low porosity, and homogeneous distribution of grains of different sizes over the total surface. The sample shows a dielectric anomaly of ferroelectric paraelectric type at 262 °C, and has non-relaxor type of diffuse phase transition. The electrical property (complex impedance Z*, complex permittivity e*, complex modulus M*) of Ba5CaTi1.94Zn0.06Nb8O30 ceramic has been investigated by non-destructive complex impedance spectroscopy (CIS) as a function of frequency at different temperatures. Grains and grain boundaries conduction is detected from a complex impedance spectrum by fitting the Nyquist plot with an appropriate electrical circuit. The Nyquist plot indicates the negative temperature coefficient of resistance (NTCR) character of Ba5CaTi1.94Zn0.06Nb8O30 ceramic. The variation of AC conductivity as a function of frequency reveals that the compound has an Arrhenius-type behavior of electrical conductivity. The DC electrical conductivities of grains and grain boundaries have been studied. The presence of non-Debye relaxations was verified by a complex modulus analysis.