Relation between Diffuse Scatterings and Fermi Surface Nesting in Iron Doped Ti-Ni Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 2337-2340
Author(s):  
Takuya Yamamoto ◽  
Mi Seon Choi ◽  
Sho Majima ◽  
Takashi Fukuda ◽  
Tomoyuki Kakeshita ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Negative Temperature Coefficient ◽  
Reciprocal Lattice ◽  
Negative Temperature ◽  
Lattice Points ◽  
Intensity Maximum ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Ni Alloys ◽  
Fe Content

We have studied diffuse scatterings appearing in Ti-(50-x)Ni-xFe (x = 6, 7, 8, 10) alloy, which shows negative temperature coefficient in electrical resistivity below a temperature Tmin. Electron diffraction pattern of each alloy exhibits diffuse scatterings below Tmin on cooling. The intensity maximum of the diffuse scatterings is located at an incommensurate position of g+<ζζ0>, where g represents reciprocal lattice points of the B2-phase. The value ζ is slightly smaller than 1/3 and decreases with increasing Fe content. The diffuse scatterings of the present alloys are well explained by the nesting effect of the Fermi surface in the B2-type structure, i.e., ζ of each alloy agrees with the length of nesting vector in the [110] direction, which is evaluated by a first-principle calculation.

Negative Temperature Coefficient of Electrical Resistivity in B2-Type Ti–Ni Alloys

1998 ◽  
Vol 37 (Part 1, No. 5A) ◽  
pp. 2535-2539 ◽  
Author(s):  
Tomoyuki Kakeshita ◽  
Takashi Fukuda ◽  
Hiroki Tetsukawa ◽  
Toshio Saburi ◽  
Koichi Kindo ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Temperature Coefficient ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Ni Alloys

Fe doped Ni-Mn-Co-O ceramics with varying Fe content as negative temperature coefficient sensors

2017 ◽  
Vol 43 (13) ◽  
pp. 10528-10532 ◽  
Author(s):  
HyukSu Han ◽  
Sungwook Mhin ◽  
Kyoung Ryeol Park ◽  
Kang Min Kim ◽  
Jung-Il Lee ◽  
...  
Keyword(s):  
Temperature Coefficient ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Fe Content

Structural, optical and electrical properties of thermal evaporated nano sized In2Te3 thin films

2018 ◽  
Vol 1 (1) ◽  
pp. 21-25
Author(s):  
R Revathi ◽  
R Karunathan
Keyword(s):  
Thin Films ◽  
Negative Temperature Coefficient ◽  
Thermal Evaporation ◽  
Structural Parameters ◽  
Negative Temperature ◽  
Resistivity Measurements ◽  
Allowed Transition ◽  
Evaporation Technique ◽  
Indium Telluride ◽  
Made In

Indium Telluride thin films were prepared by thermal evaporation technique. Films were annealed at 573K under vacuum for an hour. Both as-deposited and annealed films were used for characterization. The structural parameters were discussed on the basis of annealing effect for a film of thickness 1500 Å. Optical analysis was carried out on films of different thicknesses for both as - deposited and annealed samples. Both the as- deposited and annealed films exhibit direct and allowed transition. Electrical resistivity measurements were made in the temperature range of 303-473 K using Four-probe method. The calculated resistivity value is of the order of 10-6 ohm meter. The activation energy value decreases with increasing film thickness. The negative temperature coefficient indicates the semiconducting nature of the film.

scholarly journals Temperature Dependence of G and D’ Phonons in Monolayer to Few-Layer Graphene with Vacancies

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  
Keyword(s):  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Intrinsic Properties ◽  
Temperature Dependent ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Layer Graphene ◽  
A Value ◽  
Few Layer Graphene

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.

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