U. Köhler

Leibniz Institute for Solid State and Materials Research

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F. Steglich

Max Planck Institute for Chemical Physics of Solids

N. Oeschler

Max Planck Institute for Chemical Physics of Solids

S. Paschen

TU Wien

M. Ziese

Leipzig University

P. Esquinazi

Leipzig University

R. Höhne

Neubrandenburg University of Applied Sciences

A. Bollero

IMDEA Nanoscience

C. Emmert

Klinik für Frauenheilkunde

R. Demchyna

Max Planck Institute for Chemical Physics of Solids

B. Büchner

Leibniz Institute for Solid State and Materials Research

Cooperative Institutions

Max Planck Society

Max Planck Institute for Chemical Physics of Solids

Leibniz Institute for Solid State and Materials Research

Leipzig University

TU Dresden

Leibniz Association

Lomonosov Moscow State University

Rice University

Lviv University

University of Freiburg

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Thermoelectric Power of Correlated Compounds

NATO science for peace and security series. B, Physics and biophysics (2009)

N. Oeschler Stefanie Hartmann U. Köhler M. Deppe Peijie Sun

Degeneracy (biology)

10.1007/978-90-481-2892-1_5

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Citations (6)

Schottky barrier formation at the /Nb: interface

Journal of Magnetism and Magnetic Materials (2004)

M. Ziese U. Köhler R. Höhne A. Bollero P. Esquinazi

Metal–semiconductor junction

Interface (matter)

Schottky effect

10.1016/j.jmmm.2004.11.470

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Citations (12)

Survival and quality of life after percutaneous nephrostomy for malignant ureteric obstruction in patients with terminal cervical cancer

Archives of Gynecology and Obstetrics (1997)

C. Emmert J. Raßler U. Köhler

Percutaneous nephrostomy

Nephrostomy

Urinary diversion

Uremia

10.1007/s004040050150

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Citations (5)

New type-I clathrates with ordered Eu distribution

Physica B Condensed Matter (2006)

S. Paschen S. Budnyk U. Köhler Yurii Prots K. Hiebl

Clathrate hydrate

10.1016/j.physb.2006.03.066

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Citations (17)

Thermal expansion of RFeAsO (R=La,Ce,Pr,Sm,Gd)

Journal of Physics Conference Series (2010)

R. Klingeler L Wang U. Köhler G. Behr C. Heß

We present measurements of the thermal expansion coefficient α of polycrystalline RFeAsO (R = La,Ce,Pr,Sm,Gd).Anomalies at the magnetic ordering transitions indicate a significant magneto-elastic coupling and a negative pressure dependence of TN.The structural transitions are associated by large anomalies in α.Rare earth magnetic ordering in CeFeAsO, PrFeAsO, and SmFeAsO yields large positive anomalies at low temperatures.

10.1088/1742-6596/200/1/012088

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Citations (12)

Low-temperature study of the strongly correlated compound Ce₃Rh₄Sn₁₃

Journal of Physics Condensed Matter (2007)

U. Köhler Adam Pikul N. Oeschler T. Westerkamp A. M. Strydom

Low-temperature results of the thermodynamic and transport properties of polycrystalline Ce3Rh4Sn13 are presented. The study of the ground-state properties reveals that Kondo interactions become important below 2 K, as evidenced by a large Sommerfeld coefficient and high magnetic resistivity. At 1 K the specific heat exhibits a broad peak that is attributed to short-range magnetic order. Support is given by ac susceptibility measurements. The resistivity and the susceptibility around 80 K are dominated by effects due to the crystal electric field splitting of the Ce3+ multiplet. Additionally, clear indications for local vibrations of Sn(2) atoms within the cage-like structure are deduced from an Einstein term in the specific heat. The crystal structure is known to form two atomic cages: one in which the Ce atoms are located; the other containing the Sn(2) atoms. Although strong correlations at low T are present in this system, the thermopower is found to be surprisingly small.

Multiplet

Specific heat

Atmospheric temperature range

10.1088/0953-8984/19/38/386207

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Citations (42)

High-Pressure Synthesis and Physical Properties of the Europium-Substituted Barium Clathrate Ba8−xEuxGe43□3 (x ≤ 0.6)

Zeitschrift für anorganische und allgemeine Chemie (2005)

R. Demchyna U. Köhler Yurii Prots Walter Schnelle M. Baenitz

Abstract The new clathrate Ba 8– x Eu x Ge 43 □ 3 ( x = 0.6) was synthesized at a pressure of 1 GPa and temperatures of up to 1220 K by means of a multi‐anvil device (Walker module) and a hydraulic 1000 ton press. X‐ray powder diffraction data indicate that the crystal structure of Ba 8– x Eu x Ge 43 □ 3 ( x = 0.6, space group $Ia{\bar 3}d$ , a = 21.2588(3) Å) corresponds to that of Ba 8 Ge 43 □ 3 . Measurements of the magnetic susceptibility of Ba 8– x Eu x Ge 43 □ 3 reveal Curie‐paramagnetic behaviour and prove that the electronic state of europium corresponds to 4 f 7 , i.e., Eu 2+ . Electrical resistivity shows a metal‐like temperature dependence and ρ (300) ≈ 2mΩ cm for x = 0.6. Heat capacity measurements reveal an upturn of c p / T(T) below 7 K that is attributed to magnetic interaction of the europium ions.

Europium

Clathrate hydrate

Barium

Bar (unit)

Powder Diffraction

10.1002/zaac.200500343

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Citations (10)

Field dependence of the thermopower of CeNiSn

Journal of Physics Conference Series (2009)

U. Köhler Peijie Sun N. Oeschler T. Takabatake S. Paschen

Previously measured thermopower data of CeNiSn exhibit a significant sample dependence and non-monotonous behavior in magnetic fields. In this paper we demonstrate that the measured thermopower S(T) may contain a contribution from the huge Nernst coefficient of the compound, even in moderate fields of 2 T. A correction for this effect allows to determine the intrinsic field dependence of S(T). The observed thermopower behavior can be understood from Zeeman splitting of a V-shaped pseudogap in magnetic fields.

Pseudogap

Nernst effect

Field dependence

10.1088/1742-6596/150/4/042096

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Citations (1)

Thermal expansion ofLaFeAsO1−xFx: Evidence for high-temperature fluctuations

Physical Review B (2009)

L. Wang U. Köhler N. Leps A. Kondrat M. Nale

We present measurements of the thermal expansion coefficient alpha of polycrystalline LaFeAsO1-xFx (x <= 0.1). The magnetic and structural transitions of the samples with x <= 0.04 give rise to large anomalies in alpha(T), while the onset of superconductivity in the crystals with x >= 0.05 is not resolved. Above the structural transition, the thermal expansion coefficient of LaFeAsO is significantly enhanced. This is attributed to fluctuations, which also affect the electrical transport properties of the compound. The complete absence of these fluctuations in the superconducting samples even for x = 0.05 is taken as evidence for an abrupt first-order type of suppression of the structural and magnetic transitions upon F doping.

10.1103/physrevb.80.094512

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Citations (29)

On the road to an all-oxide spin-transistor: study of magnetotransport properties of magnetite/Nb:STO interfaces

Journal of Magnetism and Magnetic Materials (2004)

U. Köhler M. Ziese A. Bollero R. Höhne P. Esquinazi

Component (thermodynamics)

10.1016/j.jmmm.2003.12.447

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Citations (7)