P. Gegenwart

Details der Publikationsliste

Zeitraum

1997 - 2009

Anzahl

211

Co-Autoren

Quantum Griffiths phase in CePd(1-x)Rh(x) with x ~ 0.8 (2009)

Brando, M., Westerkamp, T., Deppe, M., Gegenwart, P., Geibel, C., Steglich, F.

The magnetic field dependence of the magnetisation ($M$) and the temperature dependence of the ac susceptibility ($\chi' = dM/dH$) of CePd(1-x)Rh(x) single crystals with $0.80 \leq x \leq 0.86$ are...

Quantum criticality in layered CeRhIn_{5-x}Sn_x compared with cubic CeIn$_{3-x}Sn_x (2009)

Donath, J. G., Steglich, F., Bauer, E. D., Ronning, F., Sarrao, J. L., Gegenwart, P.

We report low-temperature thermal-expansion measurements on single crystals of the {\it layered} heavy fermion system \cri ($0.3\leq x \leq 0.6$) and compare it with a previous study on the related...

Anisotropy of the low-temperature magnetostriction of Sr3Ru2O7 (2009)

Stingl, C., Perry, R. S., Maeno, Y., Gegenwart, P.

We use high-resolution capacitive dilatometry to study the low-temperature linear magnetostriction of the bilayer ruthenate Sr$_3$Ru$_2$O$_7$ as a function of magnetic field applied perpendicular to...

Quantum oscillations near a quantum critical end point in Sr3Ru2O7 (2009)

Rost, A. W., O'Farrell, E. C. T., Goh, S. K., Perry, R. S., Sutherland, M. L., ...

We report detailed investigation of quantum oscillations in Sr3Ru2O7, observed inductively (the de Haas-van Alphen effect) and thermally (the magnetocaloric effect). Working at fields from 3 T to 18...

Magnetization study on the field-induced quantum critical point in YbRh_2Si_2 (2009)

Tokiwa, Y., Geibel, C., Steglich, F., Gegenwart, P.

We study the field-induced quantum critical point (QCP) in YbRh$_2$Si$_2$ by low-temperature magnetization, $M(T)$, and magnetic Gr\"uneisen ratio, $\Gamma_{\rm mag}$, measurements and compare the...

Ferromagnetic quantum phase transition in Sr$_{1-x}$Ca$_x$RuO$_3$ thin films (2009)

Schneider, M., Moshnyaga, V., Gegenwart, P.

The ferromagnetic quantum phase transition in the perovskite ruthenate Sr$_{1-x}$Ca$_x$RuO$_3$ is studied by low-temperature magnetization and electrical resistivity measurements on thin films. The...

Growth of Sr1-xCaxRuO3 thin films by metalorganic aerosol deposition (2009)

Schneider, M., Moshnyaga, V., Gegenwart, P.

We report the growth of thin films of Sr1-xCaxRuO3 on SrTiO3 and MgO substrates by metalorganic aerosol deposition. The structure and microstructure is characterized by X-ray diffraction and...

Kondo-Cluster-Glass State near a Ferromagnetic Quantum Phase Transition (2009)

Westerkamp, T., Deppe, M., Kuechler, R., Brando, M., Geibel, C., Gegenwart, P., ...

We report on a comprehensive study of CePd$_{1-x}$Rh$_x$ $(0.6 \leq x \leq 0.95)$ poly- and single crystals close to the ferromagnetic instability by means of low-temperature ac susceptibility,...

Effects of the magnetic orderings on the dynamical conductivity: optical investigations of EuFe$_2$As$_2$ single crystals (2009)

Wu, D., Barišić, N., Drichko, N., Kaiser, S., Faridian, A., Dressel, M., ...

The magnetic, transport and optical properties of EuFe$_2$As$_2$ single crystals have been investigated parallel and perpendicular to the $ab$-plane. The anisotropy $\rho_c/\rho_{ab}\approx 8$...

Quantum oscillations in the anomalous phase in Sr3Ru2O7 (2009)

Goh, S. K., O'Farrell, E. C. T., Perry, R. S., Sutherland, M. L., Rost, A., ...

We report measurements of quantum oscillations detected in the putative nematic phase of Sr3Ru2O7. Significant improvements in sample purity allowed resolving small amplitude dHvA oscillations...

Normal-state electrical resistivity and superconducting magnetic penetration depth in Eu0.5K0.5Fe2As2 (2009)

Gasparov, V. A., Jeevan, H. S., Gegenwart, P.

We report measurements of the temperature dependence of the electrical resistivity, \rho(T), and magnetic penetration depth, \lambda(T), for polycrystalline samples of Eu_0.5K_0.5Fe_2As_2 with Tc=31...

Evolution of Quantum Criticality in CeNi_{9-x}Cu_xGe_4 (2008)

Peyker, L., Gold, C., Scherer, W., Donath, J. G., Gegenwart, P., ...

Crystal structure, specific heat, thermal expansion, magnetic susceptibility and electrical resistivity studies of the heavy fermion system CeNi_{9-x}Cu_xGe_4 (0

Divergence of the Magnetic Gr\"{u}neisen Ratio at the Field-Induced Quantum Critical Point in YbRh$_2$Si$_2$ (2008)

Tokiwa, Y., Radu, T., Gegenwart, P., Geibel, C., Steglich, F.

The heavy fermion compound YbRh$_2$Si$_2$ is studied by low-temperature magnetization $M(T)$ and specific-heat $C(T)$ measurements at magnetic fields close to the quantum critical point ($H_c=0.06$...

Possible re-entrant superconductivity in EuFe2As2 under pressure (2008)

Miclea, C. F., Nicklas, M., Jeevan, H. S., Kasinathan, D., Hossain, Z., Rosner, H., ...

We studied the temperature-pressure phase diagram of EuFe2As2 by measurements of the electrical resistivity. The antiferromagnetic spin-density-wave transition at T_0 associated with the FeAs-layers...

High-Temperature Superconductivity in Eu0.5K0.5Fe2As2 (2008)

Jeevan, H. S., Hossain, Z., Kasinathan, Deepa, Rosner, Helge, Geibel, C., Gegenwart, P.

Subsequent to our recent report of SDW type transition at 190 K and antiferromagnetic order below 20 K in EuFe2As2, we have studied the effect of K-doping on the SDW transition at high temperature...

Electrical Resistivity and Specific Heat of EuFe2As2 Single Crystals: Magnetic homologue of SrFe2As2 (2008)

Jeevan, H. S., Hossain, Z., Kasinathan, Deepa, Rosner, H., Geibel, C., Gegenwart, P.

We have grown single crystals of EuFe2As2 and investigated its electrical transport and thermodynamic properties. Electrical resistivity and specific heat measurements clearly establish the intrinsic...

Dimensional crossover of quantum critical behavior in CeCoIn$_5$ (2007)

Donath, J. G., Gegenwart, P., Steglich, F., Bauer, E. D., Sarrao, J. L.

The nature of quantum criticality in CeCoIn$_5$ is studied by low-temperature thermal expansion $\alpha(T)$. At the field-induced quantum critical point at H=5 T a crossover scale $T^\star\approx...

Quantum criticality in the cubic heavy-fermion system CeIn_{3-x}Sn_x (2006)

Kuechler, R., Gegenwart, P., Custers, J., Stockert, O., Caroca-Canales, N., Geibel, C., ...

We report a comprehensive study of CeIn$_{3-x}$Sn$_x$ $(0.55 \leq x \leq 0.8)$ single crystals close to the antiferromagnetic (AF) quantum critical point (QCP) at $x_c\approx 0.67$ by means of the...

Multiple energy scales at a quantum critical point (2006)

Gegenwart, P., Westerkamp, T., Krellner, C., Tokiwa, Y., Paschen, S., Geibel, C., ...

We report thermodynamic measurements in a magnetic-field-driven quantum critical point of a heavy fermion metal, YbRh$_2$Si$_2$. The data provide evidence for an energy scale in the equilibrium...

Quantum Criticality in doped CePd_1-xRh_x Ferromagnet (2006)

Sereni, J. G., Westerkamp, T., Kuechler, R., Caroca-Canales, N., Gegenwart, P., Geibel, C.

CePd_1-xRh_x alloys exhibit a continuous evolution from ferromagnetism (T_C= 6.5 K) at x = 0 to a mixed valence (MV) state at x = 1. We have performed a detailed investigation on the suppression of...

Low Temperature Thermodynamic Properties of the Heavy Fermion Compound YbAgGe Close to the Field-Induced Quantum Critical Point (2005)

Tokiwa, Y., Pikul, A., Gegenwart, P., Steglich, F., Bud'ko, S. L., Canfield, P. C.

We present temperature and field dependent heat capacity and magnetization data taken at temperatures down to 50 mK and in an applied magnetic field up to 11.5 Tesla for YbAgGe, a heavy-fermion...

Metamagnetic quantum criticality in Sr3Ru2O7 studied by thermal expansion (2005)

Gegenwart, P., Weickert, F., Garst, M., Perry, R. S., Maeno, Y.

We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr$_3$Ru$_2$O$_7$ as a function of magnetic field applied perpendicular to the Ruthenium-oxide planes. The...

Field-induced suppression of the heavy-fermion state in YbRh_2Si_2 (2005)

Tokiwa, Y., Gegenwart, P., Radu, T., Ferstl, J., Sparn, G., Geibel, C., ...

We report DC magnetization measurements on YbRh_2Si_2 at temperatures down to 0.04K, magnetic fields B

Two-Cannel Kondo Effect in Glass-Like ThAsSe (2005)

Cichorek, T., Sanchez, A., Gegenwart, P., Weickert, F., Wojakowski, A., Henkie, Z., ...

We present low-temperature heat and charge transport as well as caloric properties of a ThAsSe single crystal. An extra -AT1/2 term in the electrical resistivity, independent of magnetic fields as...

Ferromagnetic quantum critical fluctuations in YbRh_2(Si_{0.95}Ge_{0.05})_2 (2005)

Gegenwart, P., Custers, J., Tokiwa, Y., Geibel, C., Steglich, F.

The bulk magnetic susceptibility $\chi(T,B)$ of YbRh$_2$(Si$_{0.95}$Ge$_{0.05}$)$_2$ has been investigated %by ac-and dc-magnetometry at low temperatures and close to the field-induced quantum...

Hall-effect evolution across a heavy-fermion quantum critical point (2004)

Paschen, S., Luhmann, T., Wirth, S., Gegenwart, P., Trovarelli, O., Geibel, C., ...

A quantum critical point (QCP) develops in a material at absolute zero when a new form of order smoothly emerges in its ground state. QCPs are of great current interest because of their singular...

Grueneisen Ratio Divergence at the Quantum Critical Point in CeCu_{6-x}Ag_x (2004)

Kuechler, R., Gegenwart, P., Heuser, K., Stewart, G. R., Steglich, F.

The heavy fermion system CeCu$_{6-x}$Ag$_x$ is studied at its antiferromagnetic quantum critical point, $x_c=0.2$, by low temperature ($T\geq 50$ mK) specific heat, $C(T)$, and volume thermal...

Scaling of the magnetic entropy and magnetization in YbRh_2(Si_{0.95}Ge_{0.05})_2 (2004)

Gegenwart, P., Tokiwa, Y., Neumaier, K., Geibel, C., Steglich, F.

The magnetic entropy of YbRh_2(Si_{0.95}Ge_{0.05})_2 is derived from low-temperature ($T\geq 18$ mK) specific heat measurements. Upon field-tuning the system to its antiferromagnetic quantum critical...

Divergence of the Grueneisen Ratio at Quantum Critical Points in Heavy Fermion Metals (2003)

Kuechler, R., Oeschler, N., Gegenwart, P., Cichorek, T., Neumaier, K., Tegus, O., ...

We present low-temperature volume thermal expansion, $\beta$, and specific heat, $C$, measurements on high-quality single crystals of CeNi2Ge2 and YbRh2(Si$_{0.95}$Ge$_{0.05}$)$_2$ which are located...

The break up of heavy electrons at a quantum critical point (2003)

Custers, J., Gegenwart, P., Wilhelm, H., Neumaier, K., Tokiwa, Y., Trovarelli, O., ...

The point at absolute zero where matter becomes unstable to new forms of order is called a quantum critical point (QCP). The quantum fluctuations between order and disorder that develop at this point...

Non-Fermi liquid normal state of the Heavy Fermion superconductor UBe13 (2003)

Gegenwart, P., Langhammer, C., Helfrich, R., Oeschler, N., Lang, M., Kim, J. S., ...

Non-Fermi liquid (NFL) behavior in the normal state of the heavy-fermion superconductor UBe13 is studied by means of low-temperature measurements of the specific heat, C, and electrical resistivity,...

Tuning Heavy Fermion Systems into Quantum Criticality by Magnetic Field (2003)

Gegenwart, P., Custers, J., Tayama, T., Tenya, K., Geibel, C., Sparn, G., ...

We discuss a series of thermodynamic, magnetic and electrical transport experiments on the two heavy fermion compounds CeNi2Ge2 and YbRh2Si2 in which magnetic fields, B, are used to tune the systems...

First-Order Superconducting Phase Transition in CeCoIn5 (2002)

Bianchi,A., Movshovich,R., Oeschler,N., Gegenwart,P., Steglich,F., Thompson,J. D., ...

The superconducting phase transition in heavy fermion CeCoIn5 (T-c=2.3 K in zero field) becomes first order when the magnetic field Hparallel to[001] is greater than 4.7 T, and the transition...

Thermodynamic studies of the field-induced gap in the quasi- one-dimensional S=1/2 antiferromagnet Yb4As3 (2002)

Lang,M., Zherlitsyn,S., Wolf,B., Aoki,H., Cichorek,T., Gegenwart,P., ...

The quasi-onedimensional S = (1)/(2) antiferromagnet Yb4As3 is studied by using low-temperature measurements of the specific heat C(T,B), thermal expansion alpha(T,B) and longitudinal elastic mode...

Magnetic-Field Induced Quantum Critical Point in YbRh2Si2 (2002)

Gegenwart,P., Custers,J., Geibel,C., Neumaier,K., Tayama,T., Tenya,K., ...

We report low-temperature calorimetric, magnetic, and resistivity measurements on the antiferromagnetic (AF) heavy- fermion metal YbRh2Si2 ( T-N=70 mK) as a function of magnetic field B. While for...

Divergence of the Heavy Quasiparticle Mass at the Antiferromagnetic Quantum Critical Point in YbRh_2Si_2 (2002)

Gegenwart, P., Custers, J., Tayama, T., Tenya, K., Geibel, C., Trovarelli, O., ...

We report low temperature specific heat, C, magnetization, M, susceptibility, chi, and electrical resistivity, rho, measurements on high-quality single crystals of the heavy-fermion system...

Magnetic-Field Induced Quantum Critical Point in YbRh$_2$Si$_2$ (2002)

Gegenwart, P., Custers, J., Geibel, C., Neumaier, K., Tayama, T., Tenya, K., ...

We report low-temperature calorimetric, magnetic and resistivity measurements on the antiferromagnetic (AF) heavy-fermion metal YbRh$_2$Si$_2$ (${T_N =}$ 70 mK) as a function of magnetic field $B$....

Magnetotransport of the low-carrier density one-dimensional S=1/2 antiferromagnet Yb4As3 (2002)

Gegenwart,P., Aoki,H., Cichorek,T., Custers,J., Jaime,M., Ochiai,A., ...

The transport properties of the semimetallic quasi-one- dimensional S = 1/2 antiferromagnet Yb4As3 have been studied by performing low-temperature (T greater than or equal to 0.02 K) and high...

Specific heat and disorder in the mixed state of non-magnetic borocarbides (2002)

Lipp,D., Schneider,M., Gladun,A., Drechsler,S. L., Freudenberger,J., Fuchs,G., ...

The temperature and magnetic-field dependence of the specific heat c(p)(T, H) in the superconducting (sc) mixed state as well as the upper critical field H-c2(T) have been measured for...

First order superconducting phase transition in CeCoIn$_5$ (2002)

Bianchi, A., Movshovich, R., Oeschler, N., Gegenwart, P., Steglich, F., Thompson, J. D., ...

We investigated the magnetic field dependence of the superconducting phase transition in heavy fermion CeCoIn_5 (T_c = 2.3 K) using specific heat, magneto-caloric effect, and thermal expansion...

Influence of interchain-coupling effects on the low-T properties of the one-dimensional S=1/2 Heisenberg antiferromagnet Yb4As3 (2002)

Aoki,H., Cichorek,T., Gegenwart,P., Custers,J., Lang,M., Ochiai,A., ...

We have investigated the difference in the low-T specific heat, C(T, B), of single- and multi-domain Yb4As3 crystals in magnetic fields Bless than or equal to4 T. Upon increasing field, which was...

Low-temperature specific heat of non-charge ordered Yb4(As0.36Sb0.64)3 and (Yb0.87Lu0.13)4As3 (2002)

Cichorek,T., Aoki,H., Gegenwart,P., Lang,M., Ochiai,A., Steglich,F.

Most of the unusual low-T properties of Yb4As3, including a large specific-heat coefficient C(T)/T similar or equal to 200 mJ/K(2)mol, result from the one-dimensional S = 1/2 antiferromagnetism...

Thermodynamic and transport properties of the one-dimensional S=½ antiferromagnet Yb4As3 (2002)

Gegenwart,P., Aoki,H., Cichorek,T., Custers,J., Harrison,N., Jaime,M., ...

The semimetallic quasi-one-dimensional S = 1/2 antiferromagnet Yb4As3 has been studied by performing low-temperature (T) and high magnetic-field (B) measurements of the specific heat, C(T, B),...

Spin excitations of the one-dimensional S=1/2 Heisenberg antiferromagnet Yb4As3 under magnetic field (2002)

Kohgi,M., Iwasa,K., Mignot,J. M., Fåk,B., Hiess,A., Gegenwart,P., ...

Inelastic neutron scattering experiments on the charge ordered state of Yb4As3 have been performed under magnetic field up to about 6 T. The observed dependence of the magnetic response from the...

Effect of Ge-doping and pressure in the vicinity of the QCP of YbRh2Si2 (2002)

Trovarelli,O., Custers,J., Gegenwart,P., Geibel,C., Hinze,P., Mederle,S., ...

We present electrical resistivity (p) and AC magnetic susceptibility measurements on Ge-doped single crystals of the NFL compound YbRh2Si2. Upon producing the volume expansion (DeltaVsimilar or equal...

Low-temperature specific heat for off- and near-stoichiometric UAsSe (2002)

Cichorek,T., Henkie,Z., Wojakowski,A., Pietraszko,A., Gegenwart,P., Lang,M., ...

Two UAsSe single crystals with slight variations of the As/Se content ratio have been investigated. The development of the low-T upturn in the resistivity is accompanied by smooth decrease of the...

Influence of interchain-coupling effects on the low-T properties of the one-dimensional S=1/2 Heisenberg antiferromagnet Yb4As3 (2002)

Aoki, H., Cichorek, T., Gegenwart, P., Custers, J., Lang, M., Ochiai, A., ...

We have investigated the difference in the low-T specific heat, C(T, B), of single- and multi-domain Yb4As3 crystals in magnetic fields Bless than or equal to4 T. Upon increasing field, which was...

First-Order Superconducting Phase Transition in CeCoIn5 (2002)

Bianchi, A., Movshovich, R., Oeschler, N., Gegenwart, P., Steglich, F., Thompson, J. D., ...

The superconducting phase transition in heavy fermion CeCoIn5 (T-c=2.3 K in zero field) becomes first order when the magnetic field Hparallel to[001] is greater than 4.7 T, and the transition...

Low-temperature specific heat of non-charge ordered Yb4(As0.36Sb0.64)3 and (Yb0.87Lu0.13)4As3 (2002)

Cichorek, T., Aoki, H., Gegenwart, P., Lang, M., Ochiai, A., Steglich, F.

Most of the unusual low-T properties of Yb4As3, including a large specific-heat coefficient C(T)/T similar or equal to 200 mJ/K(2)mol, result from the one-dimensional S = 1/2 antiferromagnetism...

Low-temperature specific heat for off- and near-stoichiometric UAsSe (2002)

Cichorek, T., Henkie, Z., Wojakowski, A., Pietraszko, A., Gegenwart, P., Lang, M., ...

Two UAsSe single crystals with slight variations of the As/Se content ratio have been investigated. The development of the low-T upturn in the resistivity is accompanied by smooth decrease of the...

Thermodynamic and transport properties of the one-dimensional S=½ antiferromagnet Yb4As3 (2002)

Gegenwart, P., Aoki, H., Cichorek, T., Custers, J., Harrison, N., Jaime, M., ...

The semimetallic quasi-one-dimensional S = 1/2 antiferromagnet Yb4As3 has been studied by performing low-temperature (T) and high magnetic-field (B) measurements of the specific heat, C(T, B),...

Magnetotransport of the low-carrier density one-dimensional S=1/2 antiferromagnet Yb4As3 (2002)

Gegenwart, P., Aoki, H., Cichorek, T., Custers, J., Jaime, M., Ochiai, A., ...

The transport properties of the semimetallic quasi-one- dimensional S = 1/2 antiferromagnet Yb4As3 have been studied by performing low-temperature (T greater than or equal to 0.02 K) and high...

Magnetic-Field Induced Quantum Critical Point in YbRh2Si2 (2002)

Gegenwart, P., Custers, J., Geibel, C., Neumaier, K., Tayama, T., Tenya, K., ...

We report low-temperature calorimetric, magnetic, and resistivity measurements on the antiferromagnetic (AF) heavy- fermion metal YbRh2Si2 ( T-N=70 mK) as a function of magnetic field B. While for...

Spin excitations of the one-dimensional S=1/2 Heisenberg antiferromagnet Yb4As3 under magnetic field (2002)

Kohgi, M., Iwasa, K., Mignot, J. M., Fåk, B., Hiess, A., Gegenwart, P., ...

Inelastic neutron scattering experiments on the charge ordered state of Yb4As3 have been performed under magnetic field up to about 6 T. The observed dependence of the magnetic response from the...

Thermodynamic studies of the field-induced gap in the quasi- one-dimensional S=1/2 antiferromagnet Yb4As3 (2002)

Lang, M., Zherlitsyn, S., Wolf, B., Aoki, H., Cichorek, T., Gegenwart, P., ...

The quasi-onedimensional S = (1)/(2) antiferromagnet Yb4As3 is studied by using low-temperature measurements of the specific heat C(T,B), thermal expansion alpha(T,B) and longitudinal elastic mode...

Specific heat and disorder in the mixed state of non-magnetic borocarbides (2002)

Lipp, D., Schneider, M., Gladun, A., Drechsler, S. L., Freudenberger, J., Fuchs, G., ...

The temperature and magnetic-field dependence of the specific heat c(p)(T, H) in the superconducting (sc) mixed state as well as the upper critical field H-c2(T) have been measured for...

Effect of Ge-doping and pressure in the vicinity of the QCP of YbRh2Si2 (2002)

Trovarelli, O., Custers, J., Gegenwart, P., Geibel, C., Hinze, P., Mederle, S., ...

We present electrical resistivity (p) and AC magnetic susceptibility measurements on Ge-doped single crystals of the NFL compound YbRh2Si2. Upon producing the volume expansion (DeltaVsimilar or equal...

Specific heat and disorder in the mixed state of non-magnetic borocarbides (2001)

Lipp, D., Schneider, M., Gladun, A., Freudenberger, J., Fuchs, G., ...

The temperature and magnetic field dependence of the specific heat cp(T,H) in the superconducting mixed state as well as the upper critical field Hc2(T) have been measured for polycrystalline...

Specific heat of (Y,Lu)Ni2B2C in the mixed state (2000)

Lipp, D., Schneider, M., Gladun, A., Freudenberger, J., Fuchs, G., ...

The temperature and magnetic field dependences of the electronic specific heat in the superconducting mixed state as well as the upper critical field have been measured on a (Y,Lu)Ni2B2C series to...