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Full-Text Articles in Physics

Cubic : Bulk Thermoelectric Materials With High Figure Of Merit, Kuei Hsu, Sim Loo, Fu Guo, Wei Chen, Jeffrey Dyck, Cterid Uher, Tim Hogan, E. Polychroniadis, Mercouri Kanatzidis Feb 2004

Cubic : Bulk Thermoelectric Materials With High Figure Of Merit, Kuei Hsu, Sim Loo, Fu Guo, Wei Chen, Jeffrey Dyck, Cterid Uher, Tim Hogan, E. Polychroniadis, Mercouri Kanatzidis

Jeffrey Dyck

The conversion of heat to electricity by thermoelectric devices may play a key role in the future for energy production and utilization. However, in order to meet that role, more efficient thermoelectric materials are needed that are suitable for high-temperature applications. We show that the material system may be suitable for this purpose. With m = 10 and 18 and doped appropriately, n-type semiconductors can be produced that exhibit a high thermoelectric figure of merit of ~2.2 at 800 kelvin. In the temperature range 600 to 900 kelvin, the material is expected to outperform all reported bulk thermoelectrics, thereby earmarking …


Effect Of Sn Substituting For Sb On The Low-Temperature Transport Properties Of Ytterbium-Filled Skutterudites, J. Yang, D. Morelli, G. Meisner, W. Chen, Jeffrey Dyck, C. Uher Apr 2003

Effect Of Sn Substituting For Sb On The Low-Temperature Transport Properties Of Ytterbium-Filled Skutterudites, J. Yang, D. Morelli, G. Meisner, W. Chen, Jeffrey Dyck, C. Uher

Jeffrey Dyck

We examine the effect of alloying Sn on the Sb site of ytterbium-filled skutterudites, a promising class of thermoelectric materials. We report measurements of the Hall effect, electrical resistivity, Seebeck coefficient, and thermal conductivity between 2 and 300 K on two series of samples having different ytterbium filling fractions: Yb0.19Co4Sb12-xSnx, with x=0, 0.05, 0.1, and 0.2, and Yb0.5Co4Sb12-xSnx, with x=0.5, 0.6, 0.8, 0.83, and 0.9. We find that the substitution of Sn does not lower the electron concentration of these samples, but rather gives rise to a p-type carrier. Hall measurement data for Yb0.5Co4Sb11.17Sn0.83 can be understood in the context …


Low-Temperature Ferromagnetism And Magnetic Anisotropy In The Novel Diluted Magnetic Semiconductor Sb2−Xvxte3, Jeffrey Dyck, Wei Chen, Pavel Hájek, Petr Lošt’Ák, Ctirad Uher Feb 2002

Low-Temperature Ferromagnetism And Magnetic Anisotropy In The Novel Diluted Magnetic Semiconductor Sb2−Xvxte3, Jeffrey Dyck, Wei Chen, Pavel Hájek, Petr Lošt’Ák, Ctirad Uher

Jeffrey Dyck

We report on a novel diluted magnetic semiconductor based on the Sb2Te3 tetradymite structure doped with very low concentrations of vanadium (1–3at%). Anisotropy in the magnetic hysteresis loops and magnetoresistance are observed at temperatures below the ferromagnetic ordering temperature. A Curie temperature of 24K is observed for Sb1.97V0.03Te3.


Thermoelectric Properties Of K[Subscript 2]Bi[Subscript 8-X]Sb[Subscript X]Se[Subscript 13] Solid Solutions And Se Doping [Et Al.], Theodora Kyratski, Jeffrey Dyck, Wei Chen Dec 2001

Thermoelectric Properties Of K[Subscript 2]Bi[Subscript 8-X]Sb[Subscript X]Se[Subscript 13] Solid Solutions And Se Doping [Et Al.], Theodora Kyratski, Jeffrey Dyck, Wei Chen

Jeffrey Dyck

Our efforts to improve the thermoelectric properties of β-K2Bi8Se13, led to systematic studies of solid solutions of the type β-K2Bi8−xSbxSe13. The charge transport properties and thermal conductivities were studied for selected members of the series. Lattice thermal conductivity decreases due to the mass fluctuation generated in the lattice by the mixed occupation of Sb and Bi atoms. Se excess as a dopant was found to increase the figure-of merit of the solid solutions.


A2bi8se1 3 (A = Rb, Cs), Csbi3.67se6, And Babi2< /Inf>Se4: New Ternary Semiconducting Bismuth Selenides, Lykourgis Iordanidis, Paul Brazis, Theodora Kyratsi, John Irel, Melissa Lane, Carl Kannewurf, Wei Chen, Jeffrey Dyck, Ctirad Uher, Nishant Ghelani, Tim Hogan, Mercouri Kanatzidis Jan 2001

A2bi8se1 3 (A = Rb, Cs), Csbi3.67se6, And Babi2< /Inf>Se4: New Ternary Semiconducting Bismuth Selenides, Lykourgis Iordanidis, Paul Brazis, Theodora Kyratsi, John Irel, Melissa Lane, Carl Kannewurf, Wei Chen, Jeffrey Dyck, Ctirad Uher, Nishant Ghelani, Tim Hogan, Mercouri Kanatzidis

Jeffrey Dyck

No abstract provided.


The Influence Of Ni On The Transport Properties Of Cosb3, C. Uher, Jeffrey Dyck, W. Chen, G. Meisner, J. Yang Dec 2000

The Influence Of Ni On The Transport Properties Of Cosb3, C. Uher, Jeffrey Dyck, W. Chen, G. Meisner, J. Yang

Jeffrey Dyck

The effect of Ni doping on the Co site of the binary skutterudite CoSb3 is investigated. We measured resistivity, Hall effect, magnetoresistance, thermopower, thermal conductivity, and magnetization of a series of samples of the form Co1-xNixSb3 with x in the range x=0 to x=0.01. We find that Ni takes the tetravalent state Ni4+, assumes the d6 electronic configuration for the lower energy non-bonding orbitals, and gives an electron to the conduction band. Ni doping dramatically suppresses the thermal conductivity, changes the temperature dependence of the thermopower, and increases the carrier concentration. Low temperature anomalies in thermopower, Hall coefficient and magnetoresistance …