Specific heat, resistivity and neutron scattering studies in the Kondo lattice CeNi2Ge2

Knopp, G.; Loidl, A.; Caspary, R.; Gottwick, U.; Bredl, C. D.; Spille, H.; Steglich, F.; Murani, A.P.

doi:10.1016/0304-8853(88)90209-0

Cited by 77 publications

(40 citation statements)

References 26 publications

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“…Measurement of C was performed by the thermal relaxation method with a PPMS (Quantum Design Inc.) between 2 K and RT. S was measured by the differential method using a pair of thermo couples of Au-0.07 % Fe/Chromel in a 4 He cryostat in the same temperature range. A part of the data below 2 K was obtained by the steady-state method with two RuO 2 temperature-censors using a 3 He- 4 He dilution refrigerator.…”

Section: Methodsmentioning

confidence: 99%

“…Soon after, Miyake and Kohno theoretically supported their claim. 3) CeNi 2 Ge 2 is one of the candidates of HF systems for studying the NFL anomaly due to the proximity to the QCP, 4) and its low temperature properties have been intensively investigated. Kadowaki et al performed inelastic neutron scattering measurement at low temperatures and suggested that the spin fluctuations with a low energy of 0.6 meV evolved below 8 K are responsible for its NFL anomaly.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

et al. 2011

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We present magnetic specific heat C m and thermoelectric power S for CeNi 2 (Ge 1−x Si x ) 2 (x = 0 ∼ 0.4) in a wide range of temperatures above 1 K to 300 K. Both C m and S show a characteristic broad peak around 100 ∼ 150 K due to the Kondo effect with high Kondo temperature which is comparable to the crystalline electric field. On the other hand, C m /T and S /T synchronously increase logarithmically at low temperatures on cooling for all x investigated. The anomalous temperature dependence both in C m /T and S /T at low temperatures is interpreted as non-Fermi-liquid behavior due to the proximity to the quantum critical point for x ≤ 0.1, and due to Kondo disorder for x ≥ 0.3.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

et al. 2011

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“…[1][2][3][4][5][6] The family of CeT 2 X 2 (T= transition element, X = Ge, Si) compounds have been intensively studied because of their interesting magnetic and superconducting properties. [7][8][9][10][11][12] For example, Kondo lattice antiferromagnet CeCu 2 Si 2 is a heavy fermion superconductor that exhibits the coexistence of magnetism and superconductivity. 7,13 Pressure studies on partially Ge-substituted CeCu 2 Si 2 reveal two distinct superconducting phases associated with two quantum critical points.…”

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confidence: 99%

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

et al. 2012

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We present a complete characterization of ferromagnetic system CeIr2B2 using powder x-ray diffraction XRD, magnetic susceptibility χ(T ), isothermal magnetization M (H), specific heat C(T ), electrical resistivity ρ(T, H), and thermoelectric power S(T ) measurements. Furthermore 11 B NMR study was performed to probe the magnetism on a microscopic scale. Rietveld refinement of powder XRD data confirms that CeIr2B2 crystrallizes in CaRh2B2-type orthorhombic structure (space group fddd ). The χ(T ), C(T ) and ρ(T) data confirm bulk ferromagnetic ordering with Tc = 5.1 K. Ce ions in CeIr2B2 are in stable trivalent state. Our low-temperature C(T ) data measured down to 0.4 K yield Sommerfeld coefficient γ = 73(4) mJ/mol K 2 which is much smaller than the previously reported value of γ = 180 mJ/mol K 2 deduced from the specific heat measurement down to 2.5 K. For LaIr2B2 γ = 6(1) mJ/mol K 2 which implies the density of states at the Fermi level D(EF ) = 2.54 states/(eV f.u.) for both spin directions. The renormalization factor for quasi-particle density of states and hence for quasi-particle mass due to 4f correlations in CeIr2B2 is ≈ 12. The Kondo temperature TK ∼ 4 K is estimated from the jump in specific heat of CeIr2B2 at Tc. Both C(T ) and ρ(T ) data exhibit gapped-magnon behavior in magnetically ordered state with an energy gap Eg ∼ 3.5 K. The ρ data as a function of magnetic field H indicate a large negative magnetoresistance (MR) which is highest for T = 5 K. While at 5 K the negative MR keeps on increasing up to 10 T, at 2 K an upturn is observed near H = 3.5 T. On the other hand, the thermoelectric power data have small absolute values (S ∼ 7 µV/K) indicating a weak Kondo interaction. A shoulder in S(T ) at about 30 K followed by a minimum at ∼ 10 K is attributed to crystal electric field (CEF) effects and the onset of magnetic ordering. 11 B NMR line broadening provides strong evidence of ferromagnetic correlations below 40 K.

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“…At the lowest temperatures, the tetragonal compound CeNi 2 Ge 2 exhibits heavy Fermi liquid behavior, with C/T 380 mJ mol −1 K 2 [8] and T K 30 K [9]. Inelastic neutron spectra show two excitations [10] centered in momentum space near Q = (1/2 1/2 0) and (0 0 3/4).…”

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confidence: 99%

“…According to the published phase diagram [11], the critical concentration for the QCP in Ce(Ni 1−x Pd x ) 2 Ge 2 is x c = 0.065. Compared to CeNi 2 Ge 2 , the specific heat coefficient of Ce(Ni 0.935 Pd 0.065 ) 2 Ge 2 is 9 According to Millis [3], the SCR is a self-consistent one-loop theory that gives the same critical exponents as RG theory, but different coefficients. enhanced to the value C/T 700 mJ mol −1 K 2 and the Kondo temperature is reduced to T K 17 K [12] 10 .…”

mentioning

confidence: 99%

Quantum critical fluctuations in the heavy fermion compound Ce(Ni_0.935Pd_0.065)₂Ge₂

Wang

Poudel

Taylor

et al. 2014

J. Phys.: Condens. Matter

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Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni 0.935 Pd 0.065 ) 2 Ge 2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T ) ∼ T 3/2 and γ (T ) ∼ γ 0 − bT 1/2 ). However, for 2 T 10 K, the susceptibility and specific heat vary as logT and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.

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Specific heat, resistivity and neutron scattering studies in the Kondo lattice CeNi2Ge2

Cited by 77 publications

References 26 publications

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

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

Quantum critical fluctuations in the heavy fermion compound Ce(Ni_0.935Pd_0.065)₂Ge₂

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Specific heat, resistivity and neutron scattering studies in the Kondo lattice CeNi2Ge2

Cited by 77 publications

References 26 publications

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi2(Ge1-xSix)2

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi2(Ge1-xSix)2

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

Quantum critical fluctuations in the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2

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Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi₂(Ge_1-xSi_x)₂

Quantum critical fluctuations in the heavy fermion compound Ce(Ni_0.935Pd_0.065)₂Ge₂