A-Site Deficient SrTiO3: A Possible Phonon-Glass Electron-Crystal?

MRS Advances ◽  
2016 ◽  
Vol 1 (60) ◽  
pp. 3997-4002 ◽  
Author(s):  
Srinivasa R. Popuri ◽  
Jan-Willem G. Bos
Keyword(s):  
Thermal Conductivity ◽  
Electrical Properties ◽  
Oxygen Deficiency ◽  
Charge Carriers ◽  
Conductivity Data ◽  
Fixed Amount ◽  
Figures Of Merit ◽  
Nb Content ◽  
A Site ◽  
Electron Crystal

ABSTRACTThe thermoelectric properties of polycrystalline samples of Sr1-xLa0.67xTiO3-δ and Sr0.20La0.53Ti1−yNbyO3-δ have been investigated. The first series has a gradually increasing amount of A-site vacancies, and charge carriers linked to the oxygen deficiency. The second series has a fixed amount of A-site vacancies (27%) and variation of the Nb content was used to optimise the electrical properties. Maximum power factors of 0.6 mW m-1 K-2 for x = 0.4 and 0.4 mW m-1 K-2 for y = 0.05 were observed at 700 K. Combining these values with thermal conductivity data obtained previously, suggests that maximum figures of merit zT = 0.16 for x = 0.4 and zT = 0.2 for y = 0.05 are possible at 1000 K. This study contributes new insight on the interplay between A-site vacancies and thermoelectric performance in SrTiO3.

Partial filling of skutterudites: Optimization for thermoelectric applications

2005 ◽  
Vol 20 (12) ◽  
pp. 3234-3237 ◽  
Author(s):  
G.S. Nolas ◽  
G. Fowler
Keyword(s):  
Thermal Conductivity ◽  
Electrical Properties ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Large Range ◽  
Debye Model ◽  
Figures Of Merit ◽  
Partial Filling ◽  
Filled Skutterudites

Over the last ten years there has been substantial experimental and theoretical effort in understanding the transport properties of filled skutterudite compounds to optimize their thermoelectric properties. One such approach involves partially filling the voids in attempting to optimize the electrical properties while minimizing the thermal conductivity. We illustrate the importance of this approach by plotting and comparing the figure of merit of CoSb3 over a large range of carrier concentrations and thermal conductivity values. The thermal conductivity of partially filled skutterudites AxCo4Sb12, where A = La, Eu, and Yb, is analyzed using the Debye model to correlate the data with the type of filler atom in evaluating the role of the filler in affecting the thermal conductivity. Partial void filling has resulted in relatively high thermoelectric figures of merit at moderately high temperatures.

MeV Ion-Beam Bombardment Effects on The Thermoelectric Figures of Merit of Zn4Sb3 and ZrNiSn-Based half-heusler compounds

2007 ◽  
Vol 1020 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
C. Muntele ◽  
C. C. Smith ◽  
B. Zheng ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Measurement System ◽  
Ion Beam ◽  
Electrical Energy ◽  
Figures Of Merit ◽  
Material Systems ◽  
The Cross ◽  
Conductivity Of Thin Films

AbstractSemiconducting â-Zn4Sb3and ZrNiSn-based half-heusler compound thin films were prepared by co-evaporation for the application of thermoelectric (TE) materials. High-purity solid zinc and antimony were evaporated by electron beam to grow the â-Zn4Sb3thin film while high-purity zirconium powder and nickel tin powders were evaporated by electron beam to grow the ZrNiSn-based half-heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardments for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardments. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam can cause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ù-method measurement system to measure the cross-plane thermal conductivity ,the Van der Pauw measurement system to measure the cross-plane electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.

ChemInform Abstract: Probing the Lower Limit of Lattice Thermal Conductivity in an Ordered Extended Solid: Gd117Co56Sn112, a Phonon Glass-Electron Crystal System.

ChemInform ◽  
2012 ◽  
Vol 43 (32) ◽  
pp. no-no
Author(s):  
Devin C. Schmitt ◽  
Neel Haldolaarachchige ◽  
Yimin Xiong ◽  
David P. Young ◽  
Rongying Jin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Lower Limit ◽  
Lattice Thermal Conductivity ◽  
Crystal System ◽  
Electron Crystal

Reduction in the Thermal Conductivity of Thermoelectric Titanium Oxide by Introduction of Planar Defects

2009 ◽  
Vol 1218 ◽  
Author(s):  
Shunta Harada ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Thermal Conductivity ◽  
Titanium Oxide ◽  
Hot Pressing ◽  
Oxygen Deficiency ◽  
Nominal Composition ◽  
Titanium Oxides ◽  
X Ray Diffraction ◽  
Planar Defects ◽  
Magnéli Phase ◽  
Magneli Phase

AbstractThermoelectric properties of a homologous series of Magnéli phase titanium oxides TinO2n-1 (n = 2, 3..) have been investigated. Dense polycrystalline specimens with nominal composition of TiO2-x (x = 0.10, 0.20) have been prepared by conventional hot-pressing. X-ray diffraction analysis has revealed that prepared specimens are slightly reduced during hot-pressing. Electrical conduction is of n-type for all prepared titanium oxides and electrical resistivity and absolute values of Seebeck coefficient decrease with increasing oxygen deficiency. The carrier concentration of Magnéli phase titanium oxide increases with increasing oxygen deficiency. Lattice thermal conductivity decreases with increasing oxygen deficiency by more than 60% at room temperature and 40% at 773K compared to TiO2, which can be due to the presence of dense planar defects. The largest thermoelectric figure of merit Z, 1.6×10-4 K-1 at 773K, was obtained in TiO1.90 hot pressed specimen.

Localized vibration and avoided crossing in SrTi11O20 for oxide thermoelectrics with intrinsically low thermal conductivity

2021 ◽  
Author(s):  
Yi Li ◽  
Shinya Yamamoto ◽  
Kaleem Ahmad ◽  
Zeyad Ammar Almutairi ◽  
Koumoto Kunihito ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Chemical Bonding ◽  
State Of The Art ◽  
Electron Conduction ◽  
Low Thermal Conductivity ◽  
Oxide Thermoelectrics ◽  
Avoided Crossing ◽  
Conduction Pathway ◽  
Electron Crystal

Many state-of-the-art thermoelectric alloys achieve phonon glass and electron crystal (PGEC) via chemical bonding hierarchy (CBH), which can provide a rigid network for electron conduction pathway and loosely bonded atoms...

Composition-Dependent Electrical Conductivity of Ionic-Electronic Composite

1997 ◽  
Vol 500 ◽  
Author(s):  
M. Park ◽  
G. M. Choi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Electromotive Force ◽  
Composition Dependence ◽  
Force Measurement ◽  
Ionic Transport ◽  
Charge Carriers ◽  
Stabilized Zirconia ◽  
Ionic Charge ◽  
Polarization Technique

ABSTRACTComposition. dependence of electrical conductivity of ionic-electronic composite was camined using yttria(8mol%) stabilized zirconia-NiO composites. The contributions of ectronic and ionic charge carriers to the electrical conductivity were determined by Hebb-Vagner polarization technique and electromotive force measurement of galvanic cell. Up to 6 sol% NiO addition, the conductivity decreased since the electronic NiO acted as an insulator in onic matrix. However the ionic transport was dominant until NiO content reaches 26 vol%. Mixed conduction was observed between 26 and 68 vol% of NiO. The effects of composition on he electrical properties were explained by the microstructure and thus by the distribution of two hases.

Thermal and Electrical Conductivities of Sodium from 40 to 360 K

1972 ◽  
Vol 50 (12) ◽  
pp. 1386-1401 ◽  
Author(s):  
J. G. Cook ◽  
M. P. Van der Meer ◽  
M. J. Laubitz
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Low Temperatures ◽  
Characteristic Temperature ◽  
Published Data ◽  
Inelastic Electron ◽  
Conductivity Data ◽  
Electron Collisions ◽  
Electrical Conductivities ◽  
Flow Apparatus

We present data on the electrical and thermal resistivities and the thermopower of three pure Na specimens from 40 to 360 K. The measurements were made using a guarded longitudinal heat flow apparatus that had previously been calibrated with Au and Al. The specimens were placed in a vacuum environment using no solid inert liner.The electrical resistivity data indicate ΘR = 194 K. The thermal conductivity data show a 4% minimum near 70 K and an ice point value of 1.420 W/cm K. The reduced Lorenz function L/L0 agrees with published data at low temperatures but above 300 K levels off at approximately 0.91. On the basis of published data for liquid Na, L/L0 does not change by more than 3% at the melting point.The minimum in the thermal conductivity and a part of the high temperature deviations of L from L0 are tentatively ascribed to inelastic electron–phonon collisions having a characteristic temperature near that of longitudinal phonons. The possibility that electron–electron collisions further depress L at high temperatures is critically examined.

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