Strong temperature dependence of the Hall factor of p-type CoSb3: A re-analysis incorporating band nonparabolicity

2015 ◽  
Vol 117 (5) ◽  
pp. 055702 ◽  
Author(s):  
Y. Kajikawa
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.


2013 ◽  
Vol 58 (4) ◽  
pp. 81-86 ◽  
Author(s):  
V. Uhnevionak ◽  
A. Burenkov ◽  
C. Strenger ◽  
A. Bauer ◽  
P. Pichler

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Wupeng Cai ◽  
Shinji Muraishi ◽  
Ji Shi ◽  
Yoshio Nakamura ◽  
Wei Liu ◽  
...  

Spin reorientation transition phenomena from out-of-plane to in-plane direction with increasing temperature are observed for the 500°C annealed CoPt/AlN multilayer films with different CoPt layer thicknesses. CoPt-AlN interface and volume anisotropy contributions, favoring out-of-plane and in-plane magnetization, respectively, are separately determined at various temperatures. Interface anisotropy exhibits much stronger temperature dependence than volume contribution, hence the temperature-driven spin reorientation transition occurs. Interface anisotropy in this work consists of Néel interface anisotropy and magnetoelastic effect. Magnetoelastic effect degrades rapidly and changes its sign from positive to negative above 200°C, because of the involvement of stress state in CoPt films with temperature. By contrast, Néel interface anisotropy decays slowly, estimated from a Néel mean field model. Thus, the strong temperature dependence of CoPt-AlN interface anisotropy is dominated by the change of magnetoelastic effect.


2015 ◽  
Vol 45 (4) ◽  
pp. 2087-2091 ◽  
Author(s):  
Shirong Zhao ◽  
Heather McFavilen ◽  
Shuo Wang ◽  
Fernando A. Ponce ◽  
Chantal Arena ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5394
Author(s):  
Mani Outis ◽  
João Paulo Leal ◽  
Maria Helena Casimiro ◽  
Bernardo Monteiro ◽  
Cláudia Cristina Lage Pereira

Here we discuss the influence of two different cations on the emissive properties of the highly emissive [Eu(fod)4]− anion. The studied Eu(III) salts were [C16Pyr][Eu(fod)4] (1), and the previously reported [Chol][Eu(fod)4]. C16Pyr stands for N-cetylpyridinium, Chol for cholinium and fod for 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionate. 1 is classified as ionic liquid, with melting point close to 60 °C, and presented a luminescence quantum yield of (ϕ) 100%. Ultrabright emissive photopolymers were obtained for the first time using polysulfone as the host matrix. The films were prepared with incorporation of 10% (w/w) of 1 and [Chol][Eu(fod)4] in the polymeric matrix, which improved its thermal stability. Additionally, the luminescence of CholEu(fod)4/PSU presented a strong temperature dependence with a ratiometric thermal behavior.


1999 ◽  
Vol 607 ◽  
Author(s):  
F. Szmulowicz ◽  
A. Shen ◽  
H. C. Liu ◽  
G. J. Brown ◽  
Z. R. Wasilewski ◽  
...  

AbstractThis paper describes a study of the photoresponse of long-wavelength (LWIR) and mid-infrared (MWIR) p-type GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) as a function of temperature and QWIP parameters. Using an 8x8 envelope-function model (EFA), we designed and calculated the optical absorption of several bound-to-continuum (BC) structures, with the optimum designs corresponding to the second light hole level (LH2) coincident with the top of the well. For the temperature-dependent study, one non-optimized LWIR and one optimized MWIR samples were grown by MBE and their photoresponse and absorption characteristics measured to test the theory. The theory shows that the placement of the LH2 resonance at the top of the well for the optimized sample and the presence of light-hole-like quasi-bound states within the heavy-hole continuum for the nonoptimized sample account for their markedly different thermal and polarization characteristics. In particular, the theory predicts that, for the LWIR sample, the LH-like quasi-bound states should lead to an increased Ppolarized photoresponse as a function of temperature. Our temperature dependent photoresponse measurements corroborate most of the theoretical findings with respect to the long-wavelength threshold, shape, and polarization and temperature dependence of the spectra.


1995 ◽  
Vol 378 ◽  
Author(s):  
S.R. Smith ◽  
A.O. Evwaraye ◽  
W.C. Mitchel

AbstractWe have examined the temperature dependence of the barrier height of Au, Ag, Ni, and Al, metal-semiconductor contacts on n-type 6H-SiC, and Al metal-semiconductor contacts on p-type 6H-SiC. The barrier height was determined from the (1/C2) vs VR characteristics of the contacts at temperatures ranging from 300K to 670K. The measurements were made at 1 MHz. These measurements were compared to I-V measurements at various temperatures, and to the behavior predicted by standard models.


1989 ◽  
Vol 175 ◽  
Author(s):  
L. P. Rector ◽  
D. DeGroot ◽  
T. J. Marks ◽  
S. H. Carr

AbstractElectrically conducting composite polypyrrole/poly(p-phenyleneterephthalamide) (PPTA or KEVLAR) fibers have been prepared by chemical polymerization of pyrrole within the interstices of the hydrogen-bonded gel structure of never-dried PPTA fibers. The resultant fibers contain a uniform dispersion of polypyrrole, as evidenced by scanning electron microscopy. The temperature dependence of the electrical conductivity of these hybrid fibers is presented. The conductivity is well described by the fluctuation-induced charge transport model over the entire temperature range of interest. However, the low temperature electrical conductivity also exhibits a hoppinglike temperature dependence, and an Arrhenius-like temperature dependence is observed in the high temperature limit. Measurements of the temperaturedependent tbermopower are indicative of a p-type carrier.


2006 ◽  
Vol 527-529 ◽  
pp. 633-636 ◽  
Author(s):  
Sylvie Contreras ◽  
Marcin Zielinski ◽  
Leszek Konczewicz ◽  
Caroline Blanc ◽  
Sandrine Juillaguet ◽  
...  

We report on investigation of p-type doped, SiC wafers grown by the Modified- Physical Vapor Transport (M-PVT) method. SIMS measurements give Al concentrations in the range 1018 to 1020 cm-3, with weak Ti concentration but large N compensation. To measure the wafers’ resistivity, carrier concentration and mobility, temperature-dependant Hall effect measurements have been made in the range 100-850 K using the Van der Pauw method. The temperature dependence of the mobility suggests higher Al concentration, and higher compensation, than estimated from SIMS. Additional LTPL measurements show no evidence of additional impurities in the range of investigation, but suggest that the additional compensation may come from an increased concentration of non-radiative centers.


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