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Electrical Properties of CuO―doped SrFe0.9Sn0.1O3― δ Thick Film NTC Thermistors
YUAN Chang-Lai,WU Xiu-Fang,LIU Xin-Yu,HUANG Jing-Yue,LI Bo,LIANG Mei-Fang,MO Chong-Gui
无机材料学报 , 2011, DOI: 10.3724/sp.j.1077.2011.00387
Abstract: CuO―doped SrFe0.9Sn0.1O3― δ (CSFS) thick―film negative temperature coefficient (NTC) thermistors ( 20mol%, 30mol%, 40mol%, 50mol% ) were prepared by the screen printing method. The microstructures and electrical prop erties of CSFS thick films were determined. With the increase of CuO content, the surface morphology of thick films becomes denser. The room―temperature resistance values gradually decreases to about 0.46 M Ω and the thermistor― constant values are basically constant at around 3300 K. After the addition of CuO, SrFe0.9Sn0.1O3― δ is decomposed into various SrFe1― xSn xO3― δ ( 0.1< x<1 ) phases. By two― RQ series equivalent circuit model, impedance characteristics of the thick film containing 40mol% CuO content are investigated over the measured temperature range of 25–250 It is found that the total thick―film resistance is mainly attributed to the contribution of grain and grain boundary resistances, both of which show the typical NTC thermistor characteristics. Furthermore, the complete match of peak frequencies between the imaginary parts of impedance and electric modulus suggests that delocalized conduction is the main conduction mechanism in the thick―film NTC thermistors.
Geometrical and electrical properties of NTC polycrystalline thermistors vs. Changes of sintering parameters  [PDF]
Savi? S.M.,Aleksi? O.S.,Nikoli? P.M.,Lukovi? D.T.
Science of Sintering , 2006, DOI: 10.2298/sos0603223s
Abstract: NTC thermistor powder was made of a Mn, Ni, Fe and Co oxide mixture calcinated at 1050°C / 60 min. The powder was milled in a ball mill down to an average particle diameter of 0.9 μm. Small disc shaped pills of the powder obtained were made by pressing with a pressure of 2.5 MPa. The pills were sintered in the temperature range of 900-1400 °C for 30-240 min. The volume and specific volume resistivity change were measured as a function of sintering conditions. Microstructure development was observed using a SEM microscope. Using the results obtained, optimization of sintering parameters was performed in order to determine optimal electrical properties of the selected thermistor composition.
Semiconductor Thermistors  [PDF]
Dan McCammon
Physics , 2005, DOI: 10.1007/10933596_2
Abstract: Semiconductor thermistors operating in the variable range hopping conduction regime have been used in thermal detectors of all kinds for more than fifty years. Their use in sensitive bolometers for infrared astronomy was a highly developed empirical art even before the basic physics of the conduction mechanism was understood. Today we are gradually obtaining a better understanding of these devices, and with improvements in fabrication technologies thermometers can now be designed and built with predictable characteristics. There are still surprises, however, and it is clear that the theory of their operation is not yet complete. In this chapter we give an overview of the basic operation of doped semiconductor thermometers, outline performance considerations, give references for empirical design and performance data, and discuss fabrication issues.
Electrical Characteristics Cufe2o4 Thick Film Ceramics with Different Glass Concentrations Fired at 1000 °C for Negative Thermal Coefficient (Ntc) Thermistor  [cached]
Wiendartun Wiendartun,Dani Gustaman Syarif
Journal of Materials Science Research , 2012, DOI: 10.5539/jmsr.v1n3p70
Abstract: Fabrication of CuFe2O4 thick film ceramics utilizing Fe2O3 derived from yarosite using screen printing technique for NTC thermistor has been carried out. Effect of glass frit addition (0, 2.5, 5 weight %) has been studied. X-ray diffraction analyses (XRD) was done to know crystal structure and phases formation. SEM analyses were carried out to know microstructure of the films. Electrical properties characterization was done through measurement of electrical resistance at various temperatures (room temperature to 100°C). The XRD data showed that the films crystalize in tetragonal spinel. The SEM images showed that glass frit addition made the grain size smaller. Electrical data showed that the larger the glass frit concentration, the larger the resistance, thermistor constant and sensitivity. From the electrical characteristics data, it was known that the electrical characteristics of the CuFe2O4 thick film ceramics followed the NTC characteristic. The value of B and RRT of the produced CuFe2O4 ceramics namely B = 2215-2807oK and rRT = 6,9-16,7 M Ohm, fitted market requirement.
Sensitive germanium thermistors for cryogenic thermal detector of Tokyo dark matter search programme  [PDF]
Wataru Ootani,Yutaka Ito,Keiji Nishigaki,Yasuhiro Kishimoto,Makoto Minowa,Youiti Ootuka
Physics , 1995, DOI: 10.1016/0168-9002(95)01304-0
Abstract: Sensitive n-type and p-type germanium thermistors were fabricated by the melt doping technique and by the neutron transmutation doping (NTD) technique, respectively, aiming at a use for the cryogenic thermal detector, or bolometer of Tokyo dark matter search programme. We report on the measurements of the sensitivities of these thermistors. In particular, the p-type thermistors are sensitive enough to scale up our existing prototype LiF bolometer and realize a multiple array of the bolometers with the total absorber mass of about 1\,kg.
Preparation and Microwave Sinterability of Mn0.43Ni0.9CuFe0.67O4 NTC Thermistor Materials by Pechini Method  [PDF]
JIN Xian-Jing,CHANG Ai-Min,ZHANG Hui-Min,ZHANG Dong-Yan
无机材料学报 , 2009, DOI: 10.3724/sp.j.1077.2009.01013
Abstract: In order to obtain the NTC thermistors with small B constant (about 1900K), applied to wide temperature range, Mn0.43Ni0.9CuFe0.67O4 NTC thermistor materials prepared by Pechini method were microwave-calcined at different temperatures (650 750 nd 850 The calcined Mn0.43Ni0.9CuFe0.67O4 powders were pressed and then sintered at 1000 n a microwave furnace (multimode cavity, 2.45GHz).The crystal structure, phase compositions, morphology and particle size distribution of the samples were analyzed by FT-IR, X-ray diffraction (XRD), scanning electron microscope (SEM) and a laser particle size analyzer. The experimental results show that the electrical properties of the ceramics are strongly dependent on the calcination and sintering process. The application of microwave leads to a lower calcination temperature (650 and densified uniform microstructures. Microwave sintering can obtain the components with well uniformity of B constant and resistivity, of which the Bavg. is 1930K (deviation of 0.31%) and resistivity | SUB>avg. is 135| ¤cm (deviation of 4.55%). However, the Bavg. is 1720K (deviation of 1.47%) and resistivity |Сvg. is 78| ¤cm (deviation of 25.34%) for the conventionally sintered components. From complex impedance analysis, the grain resistance (Rb) and grain boundary resistance (Rgb) are respectively 255| and 305| for the microwavea2sintered samples. The Rb and Rgb are respectively 200| and 230| for conventionally sintered samples.
A quantitative test of Jones NTC beaming theory using CLUSTER constellation
S. Grimald, P. M. E. Décréau, P. Canu, X. Suraud, X. Vallières, F. Darrouzet,C. C. Harvey
Annales Geophysicae (ANGEO) , 2007,
Abstract: Non-thermal continuum (NTC) radiation is, with auroral kilometric radiation (AKR), one of the two electromagnetic emissions generated within the Earth's magnetosphere and radiated into space. The location of the source of NTC has been sought for several decades, with only limited success. The constellation formed by the four CLUSTER spacecraft provides the possibility of triangulation in the vicinity of the source, thus allowing progress in source localisation, while simultaneously revealing the beaming properties of NTC radio sources. We present a case event showing two beams localised on opposite sides of the magnetic equator. At any selected frequency, triangulation points to a single region source of small size. Its position is compatible with the range of possible loci of sources predicted by the radio window theory of Jones (1982) in a frame of constraints relaxed from the simple sketch proposed in early works. The analysis of similar observations from the Dynamics Explorer 1 by Jones et al. (1987) enabled the authors to claim validation of the radio window theory. CLUSTER observations, however, reveal a large beaming cone angle projected onto the ecliptic plane, a feature unobservable by Dynamics Explorer which had a different spin axis orientation. According to the radio window theory, such a large observed cone angle can only be formed by a series of point sources, each beaming in a narrow cone angle. This study demonstrates the difficulty of validating NTC linear generation mechanisms using global beaming properties alone.
A near kind of linear NTC sensitive ceramics

Mengkui WANG,

材料科学技术学报 , 2001,
Abstract: The preparation method of a new kind of SnO2-CdO-WO3 linear NTC (negative temperature coefficient) thermal sensitive ceramics was related in this paper. The electron transfer formula of this N type semiconducting ceramics was given. Factors which affect temperature - resistance characteristic curve, such as the composition of the material, heat treatment condition, the speed of the temperature rising, heat preservation time and sintering atmosphere were thoroughly studied and analyzed.
A study of the ferromagnetic transition of $SrRuO_3$ in nanometer thick bilayers with $YBa_2Cu_3O_y$, $La_{1.88}Sr_{0.12}CuO_{4-y}$, Au and Cr: Signature of injected carriers in the pseudogap regime  [PDF]
G. Aharonovich,G. Koren,E. Polturak
Physics , 2007, DOI: 10.1103/PhysRevB.76.224514
Abstract: The hypothesis regarding the existence of uncorrelated pre-formed pairs in the pseudogap regime of superconducting $YBa_2Cu_3O_y$ is tested experimentally using bilayers of $YBa_2Cu_3O_y$ and the itinerant ferromagnet $SrRuO_3$. In our study, we monitor the influence of $YBa_2Cu_3O_y$ on $T_p$, the ferromagnetic ordering temperature of $SrRuO_3$. Here, $T_p$ is the temperature of maximum dM/dT or dR/dT where M and R are the magnetization and resistance of $SrRuO_3$, respectively. We compare the results with similar measurements carried out on bilayers of $La_{1.88}Sr_{0.12}CuO_{4-y}$, $Au$ and $Cr$ with $SrRuO_3$. We find that in bilayers made of underdoped 10 nm $YBa_2Cu_3O_y$/5 nm $SrRuO_3$, the $T_p$ values are shifted to lower temperatures by up to 6-8 K as compared to $T_p\approx 140$ K of the 5 nm thick reference $SrRuO_3$ film. In contrast, in the other type of bilayers, which are not in the pseudogap regime near $T_p$, only a smaller shift of up to $\pm$2 K is observed. These differences are discussed in terms of a proximity effect, where carriers from the $YBa_2Cu_3O_y$ layer are injected into the $SrRuO_3$ layer and vice versa. We suggest that correlated electrons in the pseudogap regime of $YBa_2Cu_3O_y$ are responsible for the observed large $T_p$ shifts.
NTC and electrical properties of nickel and gold doped n-type silicon material

Dong Maojin,Chen Zhaoyang,Fan Yanwei,Wang Junhu,Tao Mingde,Cong Xiuyun,

半导体学报 , 2009,
Abstract: Silicon materials compensated by deep level impurities such as nickel and gold have negative temperature coefficient (NTC) characteristics. In this work, n-type silicon wafers are smeared by nickel chloride ethanol solution and gold chloric acid ethanol s
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