NTC Thermistor Research Articles

Structural, Optical, Relaxor and Transport Properties of a Nanocrystalline Double Perovskite: Ba2(FeMo)O6

The paper presents a synthesis (solid-state. reaction) and characterization of a lead-free double perovskite oxide Ba2(FeMo)O6 ceramic. The initial analysis using X-ray diffraction revealed that the material has a cubic crystal symmetry with a micro-lattice strain of 0.000824 and an average crystallite size of 62[Formula: see text]nm. The microstructural features and elemental composition of the prepared polycrystalline sample were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The SEM micrograph, EDX spectrum and elemental mapping show distinctly grown grains with well-defined grain boundaries, purity and distribution pattern of the grains, respectively. Raman scattering spectroscopy is a valuable tool for studying the vibrational modes to get information about structural and chemical properties of materials. The optical properties of the material were investigated using UV–Vis spectroscopy, which provides various parameters including energy bandgap for different technological applications. The electrical behavior of the synthesized double perovskite was examined through frequency- and temperature-dependent dielectric measurements as well as impedance spectroscopy. The electrical conduction in the material followed Jonscher’s power law and is supported by a thermally activated conduction mechanism. The analysis of electrical resistance versus temperature confirms negative temperature coefficient of resistance nature and can be used as NTC thermistors. The study of polarization-electric field loop opens up the possibility of the ferroelectric nature of the studied sample and also measures energy storage density, energy loss density and efficiency for searching different potential applications related to sensors. Overall, the results suggest its potential for various technological applications, such as in sensors and devices requiring specific electrical behavior or ferroelectric properties.

Widening the temperature range and improving the linearity of CaCu3Ti4O12 ceramics for high-temperature NTC thermistor application through entropy engineering strategy

The entropy engineering strategy has been used for the first time to improve the grain boundary (GB) barrier of CaCu3Ti4O12 (CCTO) ceramics, in order to solve its nonlinear problem at around 300 ℃ and expand its application in the field of high-temperature thermistors. To achieve this goal, we prepared (CaBaEuZnSr)0.2Cu3Ti4O12 (CBEZSCT) high-entropy ceramics, and the GB spontaneous segregation properties were exploited to improve the GB resistance of CBEZSCT ceramics. The results show that the GB activation energy of CBEZSCT high-entropy ceramics (0.87 eV) is higher than that of CCTO ceramics (0.7 eV), which linearizes the resistance temperature curve and extends the application temperature limit from 300° to 750 °C. The proposed method of using a high entropy strategy to tune the GB resistance of CCTO to optimize its performance is highly effective, thus providing a new way of thinking about studying high-performance CCTO materials.

Enhanced anti-aging behaviors in cubic phase CeO2 induced BaSnO3 thermosensitive ceramics

The anti-aging ability is an important index to measure the temperature measurement application of thermosensitive materials. Herein, the BaSnO3 + xCeO2 (x = 0 %, 2 %, 4 %, 7 %) ceramics were synthesized via mixing BaSnO3 with CeO2. By combining with CeO2, some Ce4+ replaces Sn4+ to improve the phase structure stability, which improves the high-temperature stability of the thermosensitive ceramic, reducing the aging coefficient from 50 % to 2.5 %. Meanwhile, the resistivity decreases with the increase of CeO2 composition, which can be attributed to the increase of Ce3+ content, resulting in the increase of the number of small polaron. With the increase of x content, thematerial constant B500/850, activation energy Ea and resistivity ρ500 of the ceramic decrease. The B values and Ea values of the thermistors are in the range of 12341–17155 K and 1.06–1.48 eV, respectively. These results indicate that BaSnO3 + xCeO2 composites are potential candidates in high temperature NTC thermistor devices.

A brownmillerite electronic material LiBiFe2O5: structural, dielectric, electrical, and ferroelectric properties for device application

ABSTRACT A lead-free brownmillerite ferroelectric material LiBiFe2O5 (LBFO) has been synthesized via a solid-state reaction technique. Using the procedure of N-TREOR method of X-ray diffraction, the crystal structure of the prepared sample is found to be monoclinic with lattice parameters: a = 13.6726 Å, b = 4.1560 Å, c = 8.5317 Å, and β = 102.89˚. Based on analysis of electrical data, the existence of Koop's and Maxwell–Wagner relaxation phenomena and dielectric relaxation in the material has been confirmed. This analysis has also shown a high impact of the dielectric permittivity (ϵr) and low tangent loss (tanδ) on using the material in some electronic devices. A detailed study of the frequency-temperature-dependent ac conductivity has suggested the presence of Jonscher's universal power law in the material. As the material has thermistor constant (β) values of 4019.26, 11535.75, and 484.36 in different temperature ranges indicating high-temperature NTC thermistor application.

Lead-free complex double perovskite SrLiFeWO6: Structural, microstructure, electrical and optical study

In this work, synthesis (solid-state reaction) and characterizations (structural, microstructure, dielectric, conductivity, Raman & UV–vis) of a newly prepared lead-free complex perovskite SrLiFeWO6 are reported. Preliminary X-ray diffraction (XRD) analysis suggests a tetragonal phase. The scanning electron microscope (SEM) micrograph and energy dispersive x-ray analysis (EDX) spectrum show the well-grown grains and sample purity. The study of Raman active lines determines the vibrational modes of the constituent molecules in the reported compound. Dispersed dielectric plots were explained by the Maxwell-Wagner polarization effect. The modulus study reveals the presence of a non-Debye type of relaxation. Jonscher's Power Law is fitted in ac conductivity data which follows a correlated barrier hopping mechanism. The direct bandgap energy of the studied sample is found to be 1.68 eV, which may be a good range for photovoltaic applications. For NTC thermistor applications, the analyzed thermistor constant and sensitivity factor are found to be within the permissible range. The idea of ferroelectric nature is opened up by the study of polarization versus electric field. The examination of current density versus electric field reveals that the sample has an ohmic character in the low region and a space charge-limited conduction (SCLC) mechanism in the higher field region.

Fabrication of polymer-derived SiBCN ceramic temperature sensor with excellent sensing performance

Sensors that can provide stability and durability in high-temperature and harsh environments are of great significance for real-time temperature monitoring. Herein, different pyrolysis temperatures of Polymer-derived silicoboron carbonitride (SiBCN) ceramics were fabricated and characterized via SEM, XRD, Raman spectroscopy and TEM. A SiBCN ceramic temperature sensor with excellent sensitivity, accuracy, repeatability, stability and response rate was developed based on the semiconductor characteristics of SiBCN ceramics. The sensor was encapsulated in a stainless-steel casing and its performance was evaluated in the range of room temperature (RT) to 980 °C utilizing a high-temperature resistance detection system. The SiBCN ceramics are typical NTC thermistors with B-values up to 3118 K and provide a sensitivity coefficient of − 3.5 %/K to − 0.2 %/K over the range of RT to 980 °C. A series of examinations verify the outstanding accuracy, repeatability and stability of the SiBCN ceramic sensor. Compared to conventional thermocouples, the SiBCN sensor has faster temperature response rate. In combination with the outstanding high-temperature thermomechanical properties of SiBCN ceramics, it is demonstrated that the designed SiBCN ceramic temperature sensor is suitable for temperature measurement in high-temperature and harsh environments.

Comprehensive and multifaceted conductive mechanisms of Mn doped BaBiO3-based ceramic NTC thermistors

Comprehensive and multifaceted conductive mechanisms of Mn doped BaBiO3-based ceramic NTC thermistors

Wafer-scale, uniform and stable Mn-Co-Fe-Zn-O thin films for NTC thermistor and its application in heat flux detecting

Wafer-scale, uniform and stable Mn-Co-Fe-Zn-O thin films for NTC thermistor and its application in heat flux detecting

Development of a novel triple perovskite barium bismuth molybdate material for thermistor-based applications

In this communication, development (synthesis and characterization) of a novel triple perovskite sample Ba3Bi2MoO9 (BBMO) is reported. The material has monoclinic crystal symmetry. A detailed study of microstructure and compositional analysis of the sample by using scanning electron microscopy (SEM) and EDX (energy dispersive X-rays) spectrum has provided the quality of the BBMO ceramic. The topological and surface roughness of the novel material has been analyzed to clarify the surface texture and compactness of the sample surface. The variation of conductivity under the alternating current of the material varies according to the Jonscher's universal power law. The high dielectric constant and low tangent loss are applicable for fabrication of various electrical instruments. The resistance decreases with an increase in temperature supports the NTCR (negative temperature coefficient of resistance) behavior, which is clarified by using TCR and β (thermistor constant) for NTC thermistor application.

Cerium-modified single perovskite CaMnO3: structural, dielectric, and transport properties

ABSTRACT In this communication, the synthesis (solid-state reaction) and characterization (structural, dielectric, and transport) of the CaMn0.9Ce0.1O3 ceramic (named, CMCO) are discussed. The CMCO has an orthorhombic crystal symmetry with an average crystallite size of 108.7 nm and lattice strain of 0.00375 respectively. The grains are distributed uniformly in a very compact manner so that highly dense material is formed and the ratio of average grain size to average crystallite size is about 21, which may be a possible reason for a better dielectric and conductivity mechanism. Raman's study confirms the presence of all constituent elements. The analysis of the dielectric properties suggests the presence of the Maxwell-Wagner type of dispersion. The study of impedance spectroscopy reveals how grains and grain boundaries play an important role to define conductivity mechanism and hence prove a non-Debye type of relaxation. The analysis of the resistance versus temperature plots supports NTC thermistor character.

Electrical properties of NiO-based composite ceramics modified by La2MO4 (M = Cu or Ni) for NTC thermistors

Electrical properties of NiO-based composite ceramics modified by La2MO4 (M = Cu or Ni) for NTC thermistors

Exploring ion migration and aging stability in Mn1.8ZnCo0.6Fe0.6O4 and La1 − xSrxMnO3 composite ceramics for NTC thermistor application

Exploring ion migration and aging stability in Mn1.8ZnCo0.6Fe0.6O4 and La1 − xSrxMnO3 composite ceramics for NTC thermistor application

A multifunctional transition metal based double perovskite Ba2(FeW)O6: Structural, microstructural, optical, electrical and ferroelectric properties

In this article, synthesis (solid-state reaction) and characterizations (XRD, SEM-EDX, RAMAN, UV–Vis, LCR & P-E measurements) of a polycrystalline double perovskite Ba2(FeW)O6 are reported. The prepared sample crystallizes in tetragonal symmetry with an average crystallite size of 60.7 nm and lattice strain of 0.00045 respectively. Vibrational modes of the molecules in the prepared sample are investigated using Raman spectroscopy. Analysis of scanning electron microscope (SEM) and energy dispersive analysis of x-ray (EDX) supports homogenous distribution of grains and compositional consistency. Optical investigation calibrates direct energy bandgap of 2.72 eV; which may be suitable for photocatalytic and photovoltaic devices. Dielectric, impedance, and modulus spectra have been studied over a wide range of frequencies (1 kHz–1 MHz) and temperatures (25 °C–500 °C). Wide dielectric dispersion at low-frequency encounters space charge polarization with the Maxwell-Wager effect. Study of impedance plots reveals negative temperature coefficient resistance (NTCR) character while existence of non-Debye relaxation mechanism is confirmed from modulus plots. Frequency dependence ac conductivity obeys Jonscher's Power Law (JPL) and confirms the presence of a non-overlapping small polaron and correlated barrier hopping process (CBH). The study of activation energy (Ea), sensitivity factor (α) and thermistor constant (β) values from resistance versus temperature supports NTC thermistor behaviour and explore the possible applications related to temperature-based sensors.

Ink-jet printed new core@shell ceramic for high stability NTC thermistors

Mn1.95Co0.21Ni0.84O4‒core@LaMnO3‒shell microbeads were in‒situ processed by an ink‒jet printing method. The composition of the LaMnO3 on the electrical properties compared with the only core Mn1.95Co0.21Ni0.84O4 (MCN) ceramic were studied. X‒ray diffraction analysis showed that the ceramics were composed mainly of cubic spinel NiMn2O4 with rhombohedral perovskite LaMnO3 phase. The X-ray photoelectron spectroscopy (XPS) results explained the ion migration occurred in the composite materials. These ceramics had negative temperature coefficients and B25/50 and Ea values of 1456–5972 K and 0.0814–0.5148 eV, respectively. Moreover, the aging coefficients (△R/R) of the bilayer core@shell structure ceramics were <0.51%, which is much lower than that of uncoated Mn1.95Co0.21Ni0.84O4 microbeads (4.1%). The grain boundaries were verified to dominate important role in the electrical property of the Mn1.95Co0.21Ni0.84O4–core@LaMnO3‒shell ceramics.

Implementation of STEM learning technology in the process of calibrating an NTC thermistor and developing an electronic thermometer based on it

The rapid development of information technology, robotics, nanotechnology, and biotechnology requires modern education to train highly qualified specialists who can support it, preparing students and students for producing creative work. The need to reform education to modern challenges is an urgent problem today. It is predicted that the most popular professions soon will be programmers, engineers, roboticists, nanotechnologists, biotechnologists, IT specialists, etc. STEM education can combine these areas into a complex, which can be implemented in different age groups. One example of the use of STEM technologies is the development and implementation of scientific and technical projects using the Arduino hardware and software complex. With the help of STEM technologies, a method for calibrating an NTC thermistor in the operating temperature range is proposed and a working model of an electronic thermometer is presented using the example of an NTC thermistor and an Arduino microcontroller.

Study of Structural, Dielectric, Electrical and Optical Properties of the Sr3CuTi4O12 Ceramics

In the present investigation, the synthesis of the strontium copper titanate [Formula: see text] ceramic by the cost-effective solid-state reaction was reported. The structural analysis suggests a single-phase tetragonal crystal symmetry with space group P4/mmm. The average crystallite size and mechanical compressive microlattice strain are found to be 65.8[Formula: see text]nm and 0.000594, respectively. The study of the field emission scanning electron microscope (FESEM) micrograph suggests that grains and grain boundaries are uniformly distributed on the sample surface with less porosity. The study of Raman lines suggests the presence of all constituent elements, which is well supported by EDAX analysis. The UV–Vis spectroscopy analysis shows that the bandgap of SCTO is about 3.2[Formula: see text]eV suitable for photovoltaic and other higher-temperature sensor applications. The decrease of dielectric constant with frequency supports the reduction of space charge polarization. The modulus analysis suggests that the immobile charge carriers at lower and defects and oxygen vacancies at higher temperatures are responsible for the thermally activated conduction process. The calculated activation energies are 4.54[Formula: see text]meV, 4.40[Formula: see text]meV, 3.39[Formula: see text]meV and 3.29[Formula: see text]meV at 1[Formula: see text]kHz, 10[Formula: see text]kHz, 100[Formula: see text]kHz and 1[Formula: see text]MHz; the decrease with the rise of the frequency confirms a thermally activated conduction process. Thermistor constant [Formula: see text], sensitivity factor [Formula: see text] and stability factor of the sample were calculated, which confirms the characteristics of the NTC thermistor. The Nyquist and Cole–Cole semicircular arcs confirm NTCR character and are found to be suitable applications for energy storage devices and thermistors.

A double perovskite BiLaCoMnO6: synthesis, microstructural, dielectric and optical properties

ABSTRACT In this paper, synthesis (solid-state reaction) and characterization (XRD, SEM, EDX, RAMAN, UV & LCR) of a double perovskite: BiLaCoMnO6 (BLCMO) are reported. The structural analysis suggests monoclinic crystal symmetry with average crystallite size = 79.6 nm and lattice strain = 0.00149 respectively. The analysis of the scanning electron microscopy (SEM) micrograph suggests the uniform distribution of grains. The analysis of energy-dispersive X-ray spectroscopy (EDX) spectrum suggests the presence of all constituent elements (Bi, La, Co, Mn & O) in both weight and atomic percentage. The study of the Raman spectrum provides information about the atomic vibration of all the constituent elements. The study of the UV visible spectrum provides of bandgap energy of 2.06 eV and impedance spectroscopy suggests a negative temperature coefficient of resistance (NTCR) character, while the modulus study predicts the presence of a non-Debye type of relaxation. The study of temperature-dependent resistance supports NTC thermistor applications.

A double perovskite BaCaZrMnO6: synthesis, microstructural dielectric, transport and optical properties

In this communication, synthesis (solid-state reaction) and characterization of a double perovskite BaCaZrMnO6 are reported. The Williamson–Hall method is used to compute average crystallite and micro-lattice strain in the prepared sample after structural analysis with X-Pert High-Score software. The sample's microstructural characteristics were investigated using a scanning electron microscope (SEM), and compositional purity was determined using energy dispersive x-ray spectroscopy (EDX). The Raman spectrum displays all atomic modes of vibration, providing information on phase, polymorphic crystallinity, and molecular interaction, as well as confirming the presence of all constituent elements. The ultraviolet visible spectrum research gives good bandgap energy for several optoelectronic devices. The impedance parameters have been measured using an impedance analyzer in a wide range of frequencies (102–106 Hz) and temperatures from 25 °C to 500 °C. The dielectric versus temperature and frequency analysis validates the Maxwell–Wanger type of dielectric dispersion. The impedance spectroscopy investigation indicates that the sample exhibits a negative temperature coefficient of resistance (NTCR), whereas the modulus analysis verifies a non-Debye type of relaxation process. The results of the ac conductivity research confirm a thermally activated relaxation process. Nyquist plot analysis reveals the NTCR character, which is well supported by Cole–Cole plots. The resistance versus temperature analysis supports the NTC thermistor nature, but the polarization–electric field (P–E) loop analysis reveals the presence of ferroelectric character, making it a strong option for temperature sensors and ferroelectric-related devices.

Structural and electrical properties of mechanically alloyed ZnO nanoceramic for NTC thermistor application

Structural and electrical properties of mechanically alloyed ZnO nanoceramic for NTC thermistor application

Investigation of pyrochlore-type A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics as negative temperature coefficient thermistors for high-temperature application

This study puts forward a series of thermosensitive materials based on A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics for high-temperature applications. The A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics were synthesized following the solid-state route and characterized using techniques involving X-Ray diffraction, scanning electron microscopy, and Raman spectroscopy. It could be verified that the A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics had pyrochlore structures with relative densities ranging from 95.8 to 97.6%. The resistance-temperature measurements confirm that these ceramics have unique oxygen-insensitive negative temperature coefficient properties. The logarithm of resistivity depends on the reciprocal of temperature with excellent linearity over a wide temperature range of 400–1300 °C. A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics also exhibited well-ageing characteristics at their maximum upper applicable temperature of 1300 °C, in addition to the high resistivity and thermal constant B value that assured high accuracy. These properties outperformed those of the majority of high-temperature negative temperature coefficient ceramics based on scheelite or perovskite structures. The results suggested that the A2Sn2O7 (A = La, Nd, Sm, or Gd) ceramics could be potentially used for fabricating high-temperature NTC thermistors.