Temperature-dependent hard X-ray photoemission spectra of ternary Tl compounds with high Seebeck coefficient

2009 ◽  
Vol 6 (5) ◽  
pp. 993-996 ◽  
Author(s):  
Kojiro Mimura ◽  
Takahiko Ishizu ◽  
Kazuya Yamamoto ◽  
Junta Takasu ◽  
Yuri Yonehira ◽  
...  
Author(s):  
Xuemei Wang ◽  
Gang Wu ◽  
Jianfeng Cai ◽  
Qiang Zhang ◽  
Junxuan Yang ◽  
...  

Seebeck coefficient describes the temperature gradient induced voltage in thermoelectrics. Usually, to obtain a high Seebeck coefficient within a wide temperature range is difficult, as it is limited by the...


2014 ◽  
Vol 492 ◽  
pp. 326-330
Author(s):  
Jie Wang ◽  
Li Peng Zhang ◽  
Yan Li

Nanometer-sized (SrxCa1-x)3Co4O9powders were prepared using the sol-gel process. Two Ca-Co-O ceramic thermoelectric materials were then prepared and characterized with X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The microstructure and thermoelectric properties of the ceramic materials were studied. The experimental results showed that the crystals of (SrxCa1-x)3CO4grew into materials with high density and low pore rate under optimal Sr-doped conditions. The (SrxCa1-x)3Co4O9ceramic materials contain directional arrays with cube-shaped grains in a layered arrangement. The crystals were fully developed and the interface between layers was clear-cut. The thermoelectric properties of (SrxCa1-x)3Co4O9ceramics were greatly improved, with high Seebeck coefficient and high electrical conductivity. The Seebeck Coefficient positively correlated with the rise of temperature.


Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.


2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
F. Boschini ◽  
M. Minola ◽  
R. Sutarto ◽  
E. Schierle ◽  
M. Bluschke ◽  
...  

AbstractIn strongly correlated systems the strength of Coulomb interactions between electrons, relative to their kinetic energy, plays a central role in determining their emergent quantum mechanical phases. We perform resonant x-ray scattering on Bi2Sr2CaCu2O8+δ, a prototypical cuprate superconductor, to probe electronic correlations within the CuO2 plane. We discover a dynamic quasi-circular pattern in the x-y scattering plane with a radius that matches the wave vector magnitude of the well-known static charge order. Along with doping- and temperature-dependent measurements, our experiments reveal a picture of charge order competing with superconductivity where short-range domains along x and y can dynamically rotate into any other in-plane direction. This quasi-circular spectrum, a hallmark of Brazovskii-type fluctuations, has immediate consequences to our understanding of rotational and translational symmetry breaking in the cuprates. We discuss how the combination of short- and long-range Coulomb interactions results in an effective non-monotonic potential that may determine the quasi-circular pattern.


1980 ◽  
Vol 51 (10) ◽  
pp. 5508 ◽  
Author(s):  
J. M. Schultz ◽  
J. S. Lin ◽  
R. W. Hendricks ◽  
R. R. Lagasse ◽  
R. G. Kepler

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Mohammed Hassan ◽  
Rfi Rafiuddin

Samples of general formula 4AgI-(1-)-2CuI, , have been prepared and investigated by XRD, DSC, and temperature-dependent conductivity studies. X-ray diffractograms showed the presence of binary system consisting of AgI and in the sample . Cu-substituted samples showed very similar diffractograms to that of the pure compound which indicates that no effect for the substitution on the nature of the binary system. DSC curves showed the presence of phase transition whose temperature increased with ratio in the system. Ionic conductivity measurements confirmed the occurrence of the phase transition and showed that the high temperature phase is superionic conducting, whose conductivity increases with the increasing amount in the system.


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.


2010 ◽  
Vol 65 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Thomas Harmening ◽  
Rainer Pöttgen

Samples of EuRu4B4 and of the new boride EuRuB4 were prepared from europium, RuB, and RuB4 precursor alloys, respectively, in sealed tantalum tubes in an induction furnace. EuRu4B4 crystallizes with the LuRu4B4 structure, a = 748.1(1), c = 1502.3(4) pm. The structure of EuRuB4 was refined on the basis of X-ray diffractometer data: Pbam, a = 599.7(1), b = 1160.7(3), c = 358.06(7) pm, wR2 = 0.0691, 474 F2 values, and 38 variables. The four crystallographically independent boron sites build up layers which consist of almost regular pentagons and heptagons which sandwich the ruthenium and europium atoms, respectively. Within the two-dimensional [B4] networks each boron atom has a slightly distorted trigonal-planar boron coordination with B-B distances in the range 172 - 186 pm. Temperature-dependent 151Eu Mössbauer spectra show stable trivalent europium for EuRu4B4 and EuRuB4


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