Complex Analysis of Electrical Resistivity Dynamics of Co82Fe4Cr3Si8B3 Amorphous Alloy under Heat Treatment

2013 ◽  
Vol 811 ◽  
pp. 72-76 ◽  
Author(s):  
Aleksandr Kotvitckii ◽  
Galina Kraynova ◽  
Anatoly Frolov ◽  
Vitaly Ivanov

In this paper the detailed analysis of thermal behavior of electrical resistivity of Co82Fe4Cr3Si8B3 amorphous alloy is made. It has been shown that within temperature range 230С <T< 5600С the structure of the alloy keeps its amorphous character and only a slight changes occurred. A high temperature (above room temperature) resistivity minimum was found at 160°C. This feature was related with Curie temperature of the alloy. It has been shown that change of electrical resistivity behavior at 350°C can be explained by reaching the Debye temperature of the alloy.

2007 ◽  
Vol 280-283 ◽  
pp. 341-344
Author(s):  
Xiao Lei Li ◽  
Yuan Fang Qu ◽  
Wei Bing Ma ◽  
Zhan Shen Zheng

Ni/BaTiO3 composite was prepared by decomposition of NiC2O4·2H2O/BaTiO3 precursor, which was prepared by precipitating of nickel in the form of oxalate into the BaTiO3 slurry. The composite must be sintered in reducing atmosphere. Otherwise NTC effect would be introduced. The prepared composite almost had no PTC effect. But PTC effect of the Ni/BaTiO3 composite can be effectively renewed by heat-treatment in air. Under a proper composition and method, the composite shows low room-temperature resistivity (ρRT=6.0 Ω·cm) and obvious PTC effect (ρmax/ρmin=102).


Author(s):  
П.А. Иванов ◽  
А.С. Потапов ◽  
М.Ф. Кудояров ◽  
М.А. Козловский ◽  
Т.П. Самсонова

AbstractIrradiation of crystalline n -type silicon carbide ( n -SiC) with high-energy (53-MeV) argon ions was used to create near-surface semi-insulating ( i -SiC) layers. The influence of subsequent heat treatment on the electrical characteristics of i -SiC layers has been studied. The most high-ohmic ion-irradiated i -SiC layers with room-temperature resistivity of no less than 1.6 × 10^13 Ω cm were obtained upon the heat treatment at 600°C, whereas the resistivity of such layers heat-treated at 230°C was about 5 × 10^7 Ω cm.


1998 ◽  
Vol 545 ◽  
Author(s):  
K. J. Proctor ◽  
F. J. DiSalvo

AbstractSingle crystals of the known ternary cerium intermetallic Ce5Cu19P12were grown by Sn flux and I2transport methods. The long axis of the black hexagonal needles was confirmed to be the c-axis by single crystal X-ray diffraction. Electrical resistivity of both single crystals and a pressed pellet was measured from 4 - 300 K; the room temperature resistivity is about 400 μΩ-cm for the needle axis of the crystals and about 5 mΩ-cm for the pressed pellet. The thermopower of the pressed pellet was found to be 34 μV/K at room temperature.


1997 ◽  
Vol 11 (09n10) ◽  
pp. 407-414 ◽  
Author(s):  
L.-S. Hsu ◽  
Y. D. Yao ◽  
Y. Y. Chen

The electrical resistivity and specific heat of NiGa were measured between 5 and 296 K and between 1.07 and 300 K, respectively, at zero magnetic field. This compound is metallic as shown from the room-temperature resistivity value (37.4 μΩ cm). The residual resistivity ratio is 1.32, which indicates the defect scattering dominates at low temperatures. The density of states at the Fermi energy and the Debye temperature obtained from the low-temperature specific-heat measurement are 1.48 states/eV formula unit and 202 K, respectively. The former is much higher than the value for NiAl. This observation suggests that the Ni d-band in NiGa is not completely filled.


1984 ◽  
Vol 37 ◽  
Author(s):  
L. H. Greene ◽  
W. L. Feldmann ◽  
J. M. Rowell ◽  
B. Batlogg ◽  
R. Hull ◽  
...  

AbstractWe report the observation of a higher degree of preferred crystalline orientation in Nb/rare earth superlattices for modulation wavelengths in the range of 200 Å to 500 Å than that exhibited by single component films. All films and multilayers are sputter deposited onto room temperature sapphire substrates. Electronic transport measurements also show that the residual resistance ratio is higher and the room temperature resistivity is lower than for multilayers of either greater or lower periodicities. Transmission electron micrographs (TEM) showing excellent layering, grain size comparable to the layer thickness, and evidence of some degree of epitaxy are presented.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taoreed O. Owolabi ◽  
Kabiru O. Akande ◽  
Sunday O. Olatunji

Doping and fabrication conditions bring about disorder in MgB2superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC). Existence of a model that directly estimatesTCof any doped MgB2superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement ofTCwastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE), that directly estimatesTCof disordered MgB2superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR) with ten experimental values of room temperature resistivity and their correspondingTCusing the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimateTCof different disordered MgB2superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation ofTCof disordered MgB2superconductors with high degree of accuracy.


2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.


2021 ◽  
Vol 1016 ◽  
pp. 906-910
Author(s):  
Xin Hua Min ◽  
Cheng Jin

In this paper,effect of the different forging processes on the microstructure and mechanical properties of the flat flat billets of TA15 titanium alloy was investigated.The flat billiets of 80 mm×150 mm×L sizes of TA15 titanium alloy are produced by four different forging processes.Then the different microstrure and properties of the flat billiets were obtained by heat treatment of 800 °C~850 °C×1 h~4h.The results show that, adopting the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling, the primary αphases content is just 10%, and there are lots of thin aciculate phases on the base. This microstructure has both high strength at room temperature and high temperature, while the properties between the cross and lengthwise directions are just the same. So the hot processing of the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling is choosed as the ideal processing for production of aircraft frame parts.


1996 ◽  
Vol 10 (20) ◽  
pp. 955-961
Author(s):  
LAUREAN HOMORODEAN ◽  
IULIU POP ◽  
ION BURDOI

The changes in the temperature dependences of the magnetic susceptibility and the electrical resistivity of a very-high-T c superconducting YBa 2 Cu 3 O 7−δ sample during the thermal cycling between the liquid-nitrogen temperature and the room temperature are studied. Some singularities corresponding to the superconducting transition, the possible existence of a super-high-temperature superconducting phase and the migration of the oxygen atoms in the Cu-O chains are emphasized on these dependencies.


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