C. Geibel

Structure and transport in multi-orbital Kondo systems

J. Kroha, S. Kirchner, G. Sellier +5

We consider Kondo impurity systems with multiple local orbitals, such as rare earth ions in a metallic host or multi--level quantum dots coupled to metallic leads. It is shown that…

High Resolution Photoemission Study on Low-T_K Ce Systems: Kondo Resonance, Crystal Field Structures, and their Temperature Dependence

D. Ehm, S. H"ufner, F. Reinert +5

We present a high-resolution photoemission study on the strongly correlated Ce-compounds CeCu_6, CeCu_2Si_2, CeRu_2Si_2, CeNi_2Ge_2, and CeSi_2. Using a normalization procedure bas…

Hall effect measurements on YbRh2Si2 and relatives in the light of electronic structure calculations

S. Friedemann, N. Oeschler, S. Wirth +7

We report experimental and theoretical investigations of the Hall effect in YbRh2Si2 and its reference compounds LuRh2Si2 and YbIr2Si2. Based on band-structure calculations we iden…

cond-mat.str-el2006

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

R. Kuechler, P. Gegenwart, J. Custers +5

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 $x_{c} \approx 0.67$ …

cond-mat1997

Interference of a first-order transition with the formation of a spin-Peierls state in alpha'-NaV2O5?

M. Koeppen, D. Pankert, R. Hauptmann +4

We present results of high-resolution thermal-expansion and specific-heat measurements on single crystalline alpha'-NaV2O5. We find clear evidence for two almost degenerate phase t…

Field-induced suppression of the heavy-fermion state in YbRh_2Si_2

Y. Tokiwa, P. Gegenwart, T. Radu +4

We report DC magnetization measurements on YbRh_2Si_2 at temperatures down to 0.04K, magnetic fields B<11.5T and under hydrostatic pressure P<1.3GPa. At ambient pressure a kink at…

cond-mat.str-el1998

Magnetic bound states in the quarter-filled ladder system $I^\pm^{'} - N a V_{2} O_{5}$ }

P. Lemmens, M. Fischer, G. Els +6

Raman scattering in the quarter-filled spin ladder system alpha'-NaV_2O_5 shows in the dimerized singlet ground state ( $T \leq T_{S P} = 35 K$ ) an unexpected sequence of three magnetic…

cond-mat.str-el2005

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

P. Gegenwart, J. Custers, Y. Tokiwa +2

The bulk magnetic susceptibility $I ¨ (T, B)$ 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-induc…

cond-mat.supr-con2021

Field-induced transition from even to odd parity superconductivity in CeRh $_{2}$ As $_{2}$

S. Khim, J. F. Landaeta, J. Banda +11

We report the discovery of two-phase unconventional superconductivity in CeRh $_{2}$ As $_{2}$ . Using thermodynamic probes, we establish that the superconducting critical field of its hig…

Interplay between Fe 3d and Ce 4f magnetism and Kondo interaction in CeFeAs_{1-x}P_{x}O probed by ^{75}As and ^{31}P NMR

R. Sarkar, M. Baenitz, A. Jesche +2

A detailed $^{31}$ P (I=1/2) and $^{75}$ As (I=3/2) NMR study on polycrystalline CeFeAs $_{1 - x}$ P $_{x}$ O alloys is presented. The magnetism of CeFeAsO changes drastically upon P subst…

cond-mat1996

Frustration induced Raman scattering in CuGeO_3

V. N. Muthukumar, Claudius Gros, Wolfgang Wenzel +7

We present experimental data for the Raman intensity in the spin-Peierls compound CuGeO_3 and theoretical calculations from a one-dimensional frustrated spin model. The theory is b…

Magnetic properties of BaCdVO(PO_4)_2: a strongly frustrated spin-1/2 square lattice close to the quantum critical regime

R. Nath, A. A. Tsirlin, H. Rosner +1

We report magnetization and specific heat measurements on polycrystalline samples of BaCdVO(PO_4)_2 and show that this compound is a S=1/2 frustrated square lattice with ferromagne…

cond-mat.str-el2017

Evolution of the Kondo lattice and non-Fermi liquid excitations in a heavy-fermion metal

S. Seiro, L. Jiao, S. Kirchner +7

Strong electron correlations can give rise to extraordinary properties of metals with renormalized quasiparticles which are at the basis of Landau's Fermi liquid theory. Near a qua…

cond-mat.str-el2015

Avoided ferromagnetic quantum critical point in CeRuPO

E. Lengyel, M. E. Macovei, A. Jesche +3

CeRuPO is a rare example of a ferromagnetic (FM) Kondo-lattice system. External pressure suppresses the ordering temperature to zero at about $p_{c} \approx 3$ GPa. Our ac-susceptibili…

Fluctuations and correlations in a frustrated S=1/2 square lattice with competing ferromagnetic and antiferromagnetic interactions: a muSR study

P. Carretta, M. Filibian, R. Nath +2

Zero and longitudinal field $I^¼$ SR measurements in Pb $_{2}$ VO(PO $_{4}$ ) $_{2}$ and BaCdVO(PO $_{4}$ ) $_{2}$ , two prototypes of the frustrated $S = 1/2$ square lattice model with competing ferroma…

Single Crystal 31P NMR Studies of the Frustrated Square Lattice Compound Pb2(VO)(PO4)2

R. Nath, Y. Furukawa, F. Borsa +4

The static and dynamic properties of V^{4+} spins (S = 1/2) in the frustrated square lattice compound Pb2(VO)(PO4)2 were investigated by means of magnetic susceptibility chi and 31…

cond-mat.str-el2022

Neutron Depolarization due to Ferromagnetism and Spin Freezing in CePd $_{1 - x}$ Rh $_{x}$

M. Seifert, P. Schmakat, M. Schulz +5

We report neutron depolarization measurements of the suppression of long-range ferromagnetism and the emergence of magnetic irreversibilities and spin freezing in CePd $_{1 - x}$ Rh$_x…

cond-mat.str-el2019

Evolution from Ferromagnetism to Antiferromagnetism in Yb(Rh1-xCox)2Si2

S. Hamann, J. Zhang, D. Jang +10

Yb(Rh1-xCox)2Si2 is a model system to address two challenging problems in the field of strongly correlated electron systems: The first is the intriguing competition between ferroma…

Antiferromagnetic ordering in the Kondo lattice system Yb $_{2}$ Fe $_{3}$ Si $_{5}$

Yogesh Singh, S. Ramakrishnan, Z. Hossain +1

Compounds belonging to the R $_{2}$ Fe $_{3}$ Si $_{5}$ series exhibit unusual superconducting and magnetic properties. Although a number of studies have been made on the first reentrant anti…

Pressure-induced change of the pairing symmetry in superconducting CeCu2Si2

E. Lengyel, M. Nicklas, H. S. Jeevan +5

Low-temperature (T) heat-capacity measurements under hydrostatic pressure of up to p=2.1 GPa have been performed on single-crystalline CeCu2Si2. A broad superconducting (SC) region…

cond-mat.str-el2011

Muon spin relaxation and neutron diffraction investigations of quadrupolar and magnetically ordered states of YbRu2Ge2

H. S. Jeevan, D. T. Adroja, A. D. Hillier +3

The magnetic and quadrupolar ordered states of polycrystalline YbRu2Ge2 have been investigated using zero-field muon spin relaxation (Î¼SR) and neutron diffraction measurements. Sp…

cond-mat.str-el2011

Evolution of magnetism in Yb(Rh_(1-x)Co_x)2Si2

C. Klingner, C. Krellner, M. Brando +10

We present a study of the evolution of magnetism from the quantum critical system YbRh2Si2 to the stable trivalent Yb system YbCo2Si2. Single crystals of Yb(Rh_(1-x)Co_x)2Si2 were…

cond-mat.str-el2004

Hall-effect evolution across a heavy-fermion quantum critical point

S. Paschen, T. Luhmann, S. Wirth +6

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…

cond-mat.str-el1998

Magnetic Bound States in Dimerized Quantum Spin Systems

P. Lemmens, M. Fischer, M. Grove +5

Magnetic bound states are a general phenomenon in low dimensional antiferromagnets with gapped singlet states. Using Raman scattering on three compounds as dedicated examples we sh…

Magnetic properties of PrPd $_{2}$ Si $_{2}$ and PrPt $_{2}$ Si $_{2}$

V. K. Anand, Z. Hossain, C. Geibel

We have investigated the two rare-earth intermetallic compounds PrPd $_{2}$ Si $_{2}$ and PrPt $_{2}$ Si $_{2}$ by means of magnetization, electrical resistivity and heat capacity measur…

Lifshitz transitions and quasiparticle de-renormalization in YbRh $_{2}$ Si $_{2}$

H. R. Naren, S. Friedemann, G. Zwicknagl +4

We study the effect of magnetic fields up to 15 T on the heavy fermion state of YbRh $_{2}$ Si $_{2}$ via Hall effect and magnetoresistance measurements down to 50 mK. Our data show anoma…

cond-mat.str-el2025

The phase diagram of CeRh $_{2}$ As $_{2}$ for out-of-plane magnetic field

P. Khanenko, J. F. Landaeta, S. Ruet +10

The heavy-fermion superconductor CeRh $_{2}$ As $_{2}$ ( $T_{c} = 0.35 K$ ) shows two superconducting (SC) phases, SC1 and SC2, when a magnetic field is applied para…

cond-mat.str-el2023

Interplay of structure and magnetism in LuFe4Ge2 tuned by hydrostatic pressure

M. O. Ajeesh, P. Materne, R. D. dos Reis +15

LuFe $_{4}$ Ge $_{2}$ crystallizes in the ZrFe $_{4}$ Si $_{2}$ -type structure, hosting chains of Fe-tetrahedra giving rise to geometric frustration and low-dimensionality. The compound orders a…

Routes to heavy-fermion superconductivity

F. Steglich, O. Stockert, S. Wirth +4

Superconductivity in lanthanide- and actinide-based heavy-fermion metals can have different microscopic origins. Among others, Cooper pair formation based on fluctuations of the va…

cond-mat.supr-con2010

CeFePO: f-d hybridization and quenching of superconductivity

M. G. Holder, A. Jesche, P. Lombardo +11

Being homologue to the new, Fe-based type of high-temperature superconductors, CeFePO exhibits magnetism, Kondo and heavy-fermion phenomena. We experimentally studied the electroni…

Superconductivity in SrFe_(2-x)Co_xAs_2: Internal Doping of the Iron Arsenide Layers

A. Leithe-Jasper, W. Schnelle, C. Geibel +1

In the electron doped compounds SrFe_(2-x)Co_xAs_2 superconductivity with T_c up to 20 K is observed for 0.2 < x < 0.4. Results of structure determination, magnetic susceptibility,…

cond-mat.supr-con2020

Electron doping of the iron-arsenide superconductor CeFeAsO controlled by hydrostatic pressure

K. Mydeen, A. Jesche, K. Meier-Kirchner +4

In the iron-pnictide material CeFeAsO not only the Fe moments, but also the local 4f moments of the Ce order antiferromagnetically at low temperatures. We elucidate on the peculiar…

cond-mat.str-el2016

Remarkable magnetostructural coupling around the magnetic transition in CeCo $_{0.85}$ Fe $_{0.15}$ Si

V. F. Correa, D. Betancourth, J. G. Sereni +2

We report a detailed study of the magnetic properties of CeCo $_{0.85}$ Fe $_{0.15}$ Si under high magnetic fields (up to 16 Tesla) measuring different physical properties such as spec…

cond-mat.supr-con2022

Field-angle dependence reveals odd-parity superconductivity in CeRh $_{2}$ As $_{2}$

J. F. Landaeta, P. Khanenko, D. C. Cavanagh +8

CeRh $_{2}$ As $_{2}$ is an unconventional superconductor with multiple superconducting phases and $T_{c} = 0.26$ K. When $H ∥ c$ , it shows a field-induced transition at $Î¼…

Determining the in-plane orientation of the ground-state orbital of CeCu2Si2

T. Willers, F. Strigari, N. Hiraoka +9

We have successfully determined the hitherto unknown sign of the B44 Stevens crystal-field parameter of the tetragonal heavy-fermion compound CeCu2Si2 using vector q dependent non-…

Ferromagnetism and superconductivity in P-doped CeFeAsO

A. Jesche, T. FÃ¶rster, J. Spehling +10

We report on superconductivity in CeFeAs1-xPxO and the possible coexistence with Ce- ferromagnetism (FM) in a small homogeneity range around x = 30% with ordering temperatures of T…

cond-mat.str-el2002

Magnetic-Field Induced Quantum Critical Point in YbRh $_{2}$ Si $_{2}$

P. Gegenwart, J. Custers, C. Geibel +5

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 ma…

cond-mat.str-el2004

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

P. Gegenwart, Y. Tokiwa, K. Neumaier +2

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 antiferromagnet…

Ferromagnetic Ordering in CeIr2B2: Transport, magnetization, specific heat and NMR studies

A. Prasad, V. K. Anand, U. B. Paramanik +5

We present a complete characterization of ferromagnetic system CeIr2B2 using powder x-ray diffraction XRD, magnetic susceptibility chi(T), isothermal magnetization M(H), specific h…

Optical study of archetypical valence-fluctuating Eu-systems

V. Guritanu, S. Seiro, J. Sichelschmidt +5

We have investigated the optical conductivity of the prominent valence fluctuating compounds EuIr2Si2 and EuNi2P2 in the infrared energy range to get new insights into the electron…

cond-mat.str-el2001

Magnetic state in URu2Si2, UPd2Al3 and UNi2Al3 probed by point contacts

Yu. G. Naidyuk, O. E. Kvitnitskaya, A. G. M. Jansen +3

The antiferromagnetic (AFM) state has been investigated in the three heavy-fermion compounds URu2Si2, UPd2Al3, and UNi2Al3 by measuring dV/dI(V) curves of point contacts at differe…

cond-mat.str-el2000

Quasi-one-dimensional spin chains in CuSiO3: an EPR study

J. Sichelschmidt, A. Loidl, M. Baenitz +3

Temperature dependent EPR studies were performed on a single crystal of CuSiO3.This recently discovered compound is isostructural with the spin-Peierls compound CuGeO3. The EPR sig…

cond-mat.supr-con2014

Itinerant and local-moment magnetism in EuCr2As2 single crystals

U. B. Paramanik, R. Prasad, C. Geibel +1

We report on the crystal structure, physical properties, and electronic structure calculations for the ternary pnictide compound EuCr2As2. X-ray diffraction studies confirmed that…

Exotic superconductivity in the coexistent phase of antiferromagnetism and superconductivity in CeCu2(Si0.98Ge0.02)2: A Cu-NQR study under hydrostatic pressure

Y. Kawasaki, K. Ishida, S. Kawasaki +5

We report a pressure ( $P$ ) effect on CeCu $_{2}$ (Si $_{0.98}$ Ge $_{0.02}$ ) $_{2}$ where an antiferromagnetic (AFM) order at $T_{N} \sim$ 0.75 K coexists with superconductivity below $T_c \si…

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

Y. Tokiwa, C. Geibel, F. Steglich +1

We study the field-induced quantum critical point (QCP) in YbRh $_{2}$ Si $_{2}$ by low-temperature magnetization, $M (T)$ , and magnetic GrÃ¼neisen ratio, $I^_{mag}$ , measurements and…

Effect of pressure on the magnetostructural transition in SrFe2As2

M. Kumar, M. Nicklas, A. Jesche +7

We present a systematic pressure study of poly- and single crystalline SrFe2As2 by electrical resistivity and X-ray diffraction measurements. SrFe2As2 exhibits a structural phase t…

cond-mat.str-el2021

Possible quadrupole density wave in the superconducting Kondo lattice CeRh2As2

D. Hafner, P. Khanenko, E. -O. Eljaouhari +12

CeRh2As2 has recently been reported to be a rare case of multi-phase unconventional superconductor [S. Khim et al., arXiv:2101.09522] close to a quantum critical point (QCP). Here,…

Far-infrared optical conductivity of CeCu2Si2

J. Sichelschmidt, A. Herzog, H. S. Jeevan +4

Journal ref.: J. Phys.: Condens. Matter 25, 065602 (2013): We investigated the optical reflectivity of the heavy-fermion metal CeCu2Si2 in the energy range 3 meV - 30 eV for temper…

Magnetic order in Pr2Pd3Ge5 and possible heavy fermion behavior in Pr2Rh3Ge5

V. K. Anand, Z. Hossain, C. Geibel

We report our results on two new ternary intermetallic compounds Pr $_{2}$ Pd $_{3}$ Ge $_{5}$ and Pr $_{2}$ Rh $_{3}$ Ge $_{5}$ based on magnetic susceptibility, magnetization, specific hea…

cond-mat.str-el1999

Elastic Constants and Charge Ordering in a'-NaV2O5

H. Schwenk, S. Zherlitsyn, B. Luethi +2

We present the temperature dependence of shear and longitudinal elastic constants in a'-NaV2O5. For the longitudinal c22 and c33 modes we find anomalies at Tc in contrast to the Sp…

CeRuPO: A rare example of a Ferromagnetic Kondo lattice

C. Krellner, N. S. Kini, E. M. Bruning +5

We have determined the physical ground state properties of the compounds CeRuPO and CeOsPO by means of magnetic susceptibility chi(T), specific heat C(T), electrical resistivity rh…

How chemical pressure affects the fundamental properties of rare-earth pnictides: an ARPES view

M. G. Holder, A. Jesche, P. Lombardo +9

Angle-resolved photoelectron spectroscopy, supplemented by theoretical calculations has been applied to study the electronic structure of heavy-fermion material CeFePO, a homologue…

cond-mat.str-el2000

CuSiO_3 : a quasi - one - dimensional S=1/2 antiferromagnetic chain system

M. Baenitz, C. Geibel, M. Dischner +5

CuSiO_3, isotypic to the spin - Peierls compound CuGeO_3, was discovered recently as a metastable decomposition product of the silicate mineral dioptase, Cu_6Si_6O_{18}\cdot6H_2O.…

cond-mat1997

Magnetic Resonance in the Spin-Peierls compound $I^\pm^{'} - N a V_{2} O_{5}$

S. Schmidt, W. Palme, B. LÃ¼thi +3

We present results from magnetic resonance measurements for 75-350 GHz in $I^\pm$ '-NaV $_{2}$ O $_{5}$ . The temperature dependence of the integrated intensity indicates that we observe t…

cond-mat.str-el2005

Non-Fermi liquid states in the pressurized $C e C u_{2} (S i_{1 - x} G e_{x})_{2}$ system: two critical points

H. Q. Yuan, F. M. Grosche, M. Deppe +3

In the archetypal strongly correlated electron superconductor CeCu $_{2}$ Si $_{2}$ and its Ge-substituted alloys CeCu $_{2}$ (Si $_{1 - x}$ Ge $_{x}$ ) $_{2}$ two quantum phase transitions -- one mag…

Thermal and Electrical Transport across a Magnetic Quantum Critical Point

H. Pfau, S. Hartmann, U. Stockert +11

A quantum critical point (QCP) arises at a continuous transition between competing phases at zero temperature. Collective excitations at magnetic QCPs give rise to metallic propert…

Why could Electron Spin Resonance be observed in a heavy fermion Kondo lattice?

B. I. Kochelaev, S. I. Belov, A. M. Skvortsova +5

We develop a theoretical basis for understanding the spin relaxation processes in Kondo lattice systems with heavy fermions as experimentally observed by electron spin resonance (E…

cond-mat.supr-con1997

Normal-State Hall Effect and the Insulating Resistivity of High-T_c Cuprates at Low Temperatures

Yoichi Ando, G. S. Boebinger, A. Passner +5

The normal-state Hall coefficient R_H and the in-plane resistivity Ï_{ab} are measured in La-doped Bi_{2}Sr_{2}CuO_{y} (T_c \simeq 13 K) single crystals and La_{2-x}Sr_{x}CuO_{4}…

Evidence for a Non-Fermi-Liquid Phase in Ge-Substituted YbRh2Si2

J. Custers, P. Gegenwart, C. Geibel +3

The canonical view of heavy fermion quantum criticality assumes a single quantum critical point separating the paramagnet from the antiferromagnet. However, recent experiments on Y…

cond-mat.str-el2020

Gradual pressure-induced enhancement of magnon excitations in CeCoSi

S. E. Nikitin, D. G. Franco, J. Kwon +6

CeCoSi is an intermetallic antiferromagnet with a very unusual temperature-pressure phase diagram: at ambient pressure it orders below $T_{N} = 8.8$ K, while application o…

Kondo-Cluster-Glass State near a Ferromagnetic Quantum Phase Transition

T. Westerkamp, M. Deppe, R. Kuechler +5

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 su…

Electron Spin Resonance of the ferromagnetic Kondo lattice CeRuPO

T. FÃ¶rster, J. Sichelschmidt, C. Krellner +2

The spin dynamics of the ferromagnetic Kondo lattice CeRuPO is investigated by Electron Spin Resonance (ESR) at microwave frequencies of 1, 9.4, and 34~GHz. The measured resonance…

Magnetic order and spin dynamics in the proximity of a ferromagnetic quantum critical point: A Î¼SR study of YbNi4P2

J. Spehling, M. GÃ¼nther, C. Krellner +5

The local 4f-electronic spin dynamics and magnetic order in YbNi4P2 were studied by means of muon-spin relaxation measurements. Zero-field muon-spin relaxation proves static magnet…

Magnetically driven superconductivity in CeCu2Si2

O. Stockert, J. Arndt, E. Faulhaber +8

The origin of unconventional superconductivity, including high-temperature and heavy-fermion superconductivity, is still a matter of controversy. Spin excitations instead of phonon…

cond-mat.str-el2014

Local character of the highest antiferromagnetic Ce-system CeTi{1-x}Sc{x} Ge

J. G. Sereni, P. Pedrazzini, M. Gomez Berisso +5

The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with Tn=47K, but its local or itinerant nature was not deeply investigated yet. I…

Low temperature properties of the Electron Spin Resonance in YbRh2Si2

J. Sichelschmidt, T. Kambe, I. Fazlishanov +12

We present the field and temperature behavior of the narrow Electron Spin Resonance (ESR) response in YbRh2Si2 well below the single ion Kondo temperature. The ESR g factor reflect…

cond-mat.str-el1997

Effects of in-chain and off-chain substitutions on spin fluctuations in the spin-Peierls compound CuGeO_3

P. Lemmens, M. Fischer, G. GÃ¼ntherodt +6

The effect of in-chain and off-chain substitutions on 1D spin fluctuations in the spin-Peierls compound CuGeO_3 has been studied using Raman scattering in order to understand the i…

cond-mat.mtrl-sci2013

Valence Fluctuation in CeMo2Si2C

U. B. Paramanik, Anupam, U. Burkhard +3

We report on the valence fluctuation of Ce in CeMo $_{2}$ Si $_{2}$ C as studied by means of magnetic susceptibility $I ¨ (T)$ , specific heat $C (T)$ , electrical resistivity $I ¨ (T)$ and x…

Electron Spin Resonance of the Yb 4f moment in Yb(Rh1-xCox)2Si2

T. Gruner, J. Sichelschmidt, C. Klingner +3

[published in Phys. Rev. B 85, 035119 (2012)] The evolution of spin dynamics from the quantum critical system YbRh2Si2 to the stable trivalent Yb system YbCo2Si2 was investigated b…

Anisotropic electron spin resonance of YbIr2Si2

T. Gruner, J. Wykhoff, J. Sichelschmidt +3

A series of electron spin resonance (ESR) experiments were performed on a single crystal of the heavy fermion metal YbIr2Si2 to map out the anisotropy of the ESR-intensity I_ESR wh…

cond-mat.str-el2001

Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2

F. Reinert, D. Ehm, S. Schmidt +5

We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly-correlated Ce system CeCu $_{2}$ Si $_{2}$ . Exploiting the thermal broadening of the F…

cond-mat.str-el2017

Ising-type Magnetic Anisotropy in CePd $_{2}$ As $_{2}$

M. O. Ajeesh, T. Shang, W. B. Jiang +6

We investigated the anisotropic magnetic properties of CePd $_{2}$ As $_{2}$ by magnetic, thermal and electrical transport studies. X-ray diffraction confirmed the tetragonal ThCr $_{2}$ Si$_…

cond-mat.str-el2001

Ce-L3-XAS study of the temperature dependence of the 4f occupancy in the Kondo system Ce2Rh3Al9

C. Grazioli, Z. Hu, M. S. Golden +3

We have used temperature dependent x-ray absorption at the Ce-L3 edge to investigate the recently discovered Kondo compound Ce2Rh3Al9. The systematic changes of the spectral linesh…

Single crystal growth and anisotropy of CeRuPO

C. Krellner, C. Geibel

We report on the single crystal growth of the ferromagnetic Kondo lattice system CeRuPO using a Sn flux method. Magnetic susceptibility and electrical resistivity measurements indi…

Magnetic and structural transitions in layered FeAs systems: AFe2As2 versus RFeAsO compounds

C. Krellner, N. Caroca-Canales, A. Jesche +3

Resistivity, specific heat and magnetic susceptibility measurements performed on SrFe2As2 samples evidence a behavior very similar to that observed in LaFeAsO and BaFe2As2 with the…

cond-mat.str-el2020

Putative quantum critical point in the itinerant magnet ZrFe $_{4}$ Si $_{2}$ with a frustrated quasi-one-dimensional structure

M. O. Ajeesh, K. Weber, C. Geibel +1

The Fe sublattice in the compound ZrFe $_{4}$ Si $_{2}$ features geometrical frustration and quasi-one-dimensionality. We therefore investigated the magnetic behavior in ZrFe $_{4}$ Si $_{2}$ an…

Effect of Ni-doping on magnetism and superconductivity in Eu0.5K0.5Fe2As2

Anupam, V. K. Anand, P. L. Paulose +3

The effect of Ni-doping on the magnetism and superconductivity in Eu0.5K0.5Fe2As2 has been studied through a systematic investigation of magnetic and superconducting properties of…

cond-mat.str-el1996

Substitution effects on spin fluctuations in the spin-Peierls compound CuGeO_3

M. Fischer, P. Lemmens, G. GÃ¼ntherodt +4

Using Raman scattering we studied the effect of substitutions on 1D spin fluctuations in CuGeO_3 observed as a spinon continuum in frustration induced exchange scattering. For temp…

High-Temperature Superconductivity in Eu0.5K0.5Fe2As2

H. S. Jeevan, Z. Hossain, Deepa Kasinathan +3

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…

Possible re-entrant superconductivity in EuFe2As2 under pressure

C. F. Miclea, M. Nicklas, H. S. Jeevan +6

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 wi…

cond-mat.str-el2006

Quantum phase transition in the heavy-fermion compound YbIr $_{2}$ Si $_{2}$

H. Q. Yuan, M. Nicklas, Z. Hossain +2

We investigate the pressure-temperature phase diagram of YbIr $_{2}$ Si $_{2}$ by measuring the electrical resistivity $I ¨ (T)$ . In contrast to the widely investigated YbRh $_{2}$ Si $_{2}$ , YbIr…

cond-mat.str-el2016

Unique magnetic structure of YbCo $_{2}$ Si $_{2}$

N. Mufti, K. Kaneko, A. Hoser +4

We report on the results of powder and single crystal neutron diffraction to investigate the magnetic order in YbCo $_{2}$ Si $_{2}$ below the NÃ©el temperature $T_{N} = 1.7$ K in det…

Interplay between superconductivity and magnetism in K-doped EuFe2As2

Anupam, P. L. Paulose, H. S. Jeevan +2

Superconductivity is found in 50% K-doped EuFe2As2 sample below 33 K. Our results of electrical resistivity, magnetic susceptibility and 57Fe and 151Eu Mossbauer spectroscopy provi…

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: magnetic properties of M(VO)2(PO4)2 (M = Ca and Sr)

R. Nath, A. A. Tsirlin, E. E. Kaul +4

We present a detailed investigation of the magnetic properties of complex vanadium phosphates M(VO)2(PO4)2 (M = Ca, Sr) by means of magnetization, specific heat, 31P NMR measuremen…

cond-mat.str-el2002

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

P. Gegenwart, J. Custers, T. Tayama +4

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

cond-mat.str-el2018

Similar temperature scale for valence changes in Kondo lattices with different Kondo temperatures

K. Kummer, C. Geibel, C. Krellner +4

The Kondo model predicts that both the valence at low temperatures and its temperature dependence scale with the characteristic energy T_K of the Kondo interaction. Here, we study…

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

R. Kuechler, N. Oeschler, P. Gegenwart +8

We present low-temperature volume thermal expansion, $I^^{2}$ , and specific heat, $C$ , measurements on high-quality single crystals of CeNi2Ge2 and YbRh2(Si $_{0.95}$ Ge $_{0.05}$ ) $_{2}$ wh…

Tuning Heavy Fermion Systems into Quantum Criticality by Magnetic Field

P. Gegenwart, J. Custers, T. Tayama +8

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 t…

Multiple energy scales at a quantum critical point

P. Gegenwart, T. Westerkamp, C. Krellner +6

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 th…

Effect of chemical substitution and pressure on YbRh2Si2

M. Nicklas, M. E. Macovei, J. Ferstl +3

We carried out electrical resistivity experiments on (Yb,La)Rh2Si2 and on Yb(Rh,Ir)2Si2 under pressure and in magnetic fields. YbRh2Si2 exhibits a weak antiferromagnetic transition…

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

H. S. Jeevan, Z. Hossain, Deepa Kasinathan +3

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

Strong coupling between magnetic and structural order parameters in SrFe2As2

A. Jesche, N. Caroca-Canales, H. Rosner +11

X-ray and Neutron diffraction as well as muon spin relaxation and MÃ¶ssbauer experiments performed on SrFe $_{2}$ As $_{2}$ polycrystalls confirm a sharp first order transition at $T_0 =…

Hydrostatic and chemical pressure tuning of CeFeAs_1-xP_xO single crystals

K. Mydeen, E. Lengyel, A. Jesche +2

We carried out a combined P-substitution and hydrostatic pressure study on CeFeAs_1-xP_xO single crystals in order to investigate the peculiar relationship of the local moment magn…

cond-mat.str-el2002

Spin dynamics in a structurally ordered non-Fermi liquid compound: YbRh_2Si_2

K. Ishida, D. E. MacLaughlin, O. O. Bernal +5

Muon spin relaxation (muSR) experiments have been carried out at low temperatures in the non-Fermi-liquid heavy-fermion compound YbRh_2Si_2. The longitudinal-field muSR relaxation…

cond-mat.str-el2019

V. F. Correa, A. G. VillagrÃ¡n Asiares, D. Betancourth +8

A very strong magnetoelastic effect in the CeCo $_{1 - x}$ Fe $_{x}$ Si alloys is reported. The strength of the magnetostrictive effect can be tuned upon changing $x$ . The moderate low-t…

cond-mat.supr-con2017

Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu2Si2

T. Yamashita, T. Takenaka, Y. Tokiwa +16

In exotic superconductors including high- $T_{c}$ copper-oxides, the interactions mediating electron Cooper-pairing are widely considered to have a magnetic rather than the convention…

cond-mat.mtrl-sci2011

Phase separation and frustrated square lattice magnetism of Na1.5VOPO4F0.5

A. A. Tsirlin, R. Nath, A. M. Abakumov +7

Crystal structure, electronic structure, and magnetic behavior of the spin-1/2 quantum magnet Na1.5VOPO4F0.5 are reported. The disorder of Na atoms leads to a sequence of structura…