Non-enhancement of thermoelectric-power coefficient of at low temperatures

Isikawa, Yosikazu; Ikeno, Tsuyoshi; Sugihara, T.; Kinoshita, Toshihiro; Kuwai, Tomohiko; Mizushima, T.

doi:10.1016/j.jmmm.2006.10.047

Cited by 6 publications

(7 citation statements)

References 10 publications

(13 reference statements)

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“…As shown in figure 6, the feature of C 4f (T ) above T N is not a tail due to the magnetic fluctuation, but a plateau. The quadrupole fluctuations may cause a plateau of C(T )/T at low temperatures, as has been observed in PrAg 2 In [2] and PrCu 2 In [4], in which the ground states have quadrupole moments and C(T )/T is enhanced at low temperatures.…”

Section: Magnetic Entropy S 4 Fmentioning

confidence: 69%

“…The 4f 2 electron configuration of Pr 3+ is compared with the 5f 2 of U 4+ . However, 4f 2 has more localized characters than 5f 2 . So, the effect of the crystalline electric field (CEF) of 4f 2 is more distinct than that of 5f 2 .…”

Section: Introductionmentioning

confidence: 99%

“…The state of 4f 2 electrons is more strictly lifted by the CEF than that of 5f 2 electrons. The 4f 2 configuration of Pr 3+ can have a non-magnetic, non-Kramers 3 doublet as its CEF ground state (GS), and the quadrupole moment of the 3 doublet might interact with the conduction electrons to produce strongly-correlated properties; examples are found in PrAg 2 In [1][2][3], PrCu 2 In [4], PrPb 3 [5] and PrMg 3 [6]. The first two material types are characterized with enhanced Sommerfeld coefficients γ ∼ 6.5 J mol −1 K −2 and γ ∼ 1 J mol −1 K −2 , respectively.…”

Section: Introductionmentioning

confidence: 99%

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Heavy-electron-like behavior in cubic PrCu₄Au

Zhang

Mizushima²,

Kuwai³

et al. 2009

J. Phys.: Condens. Matter

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The magnetization M(H), magnetic susceptibility χ(T), electrical resistivity ρ(T) and specific heat C(T) properties of PrCu(4)Au have been investigated. A clear antiferromagnetic transition T(N) is observed at 2.5 K in C(T) and χ(T). The internal magnetic field at the Pr nucleus, H(HF), is obtained to be 195 T from the nuclear specific heat observed in C(T) below 0.7 K. The ground state of Pr 4f(2) in the cubic crystalline electric field is inferred to be a magnetic triplet Γ(5) from the magnitude of the magnetization at 2 K, which coincides with the value of the 4f(2) magnetic moments deduced from H(HF). The large value of the electronic specific heat coefficient, γ, remains at the zero-temperature limit even in external magnetic fields. On the other hand, the entropy up to T(N) is somewhat less than Rln3. These anomalous heavy-electron-like behaviors probably originate in the fact that both the magnetic moments and the quadrupole moments are involved in the ground state of Pr 4f(2).

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Section: Magnetic Entropy S 4 Fmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heavy-electron-like behavior in cubic PrCu₄Au

Zhang

Mizushima²,

Kuwai³

et al. 2009

J. Phys.: Condens. Matter

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“…However, the thermoelectric power is not enhanced and the absolute value is comparable to that of the La counterpart, indicating the conduction electrons at the Fermi level could not correlate strongly with the 4 f 2 electrons. [16,17] Moreover, in the specific heat measurements using a high-quality single crystal of PrAg 2 In with the residual resistivity ratio of RRR = 14, a cusp-type anomaly manifests itself at 0.33 K, indicating the relationship between the sample quality and occurrence of a phase transition. [18] Thereby, the absence of the quadrupole order may result from symmetry lowering due to the atomic disorder inherent in the Heusler-type structure.…”

mentioning

confidence: 95%

“…[18] Thereby, the absence of the quadrupole order may result from symmetry lowering due to the atomic disorder inherent in the Heusler-type structure. [16,17] Recently, coexistence of quadrupole orders and superconductivity has been observed in non-Kramers doublet systems PrT 2 Zn 20 (T = Ir, Rh) [19][20][21][22], and PrT 2 Al 20 (T = Ti, V), [24][25][26][27] which suggests the superconducting pair could be mediated by quadrupole fluctuations. Furthermore, non-Fermi liquid (NFL) behaviors of the electrical resistivity ρ(T ) and the specific heat C(T ) were observed not only in PrIr 2 Zn 20 and PrRh 2 Zn 20 [23,28] but also in a diluted Pr system Y(Pr)Ir 2 Zn 20 [29], indicating possible manifestation of the quadrupole Kondo effect.…”

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confidence: 99%

Hindered Quadrupole Order in PrMgNi₄ with a Nonmagnetic Doublet Ground State

et al. 2019

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Structural, transport and magnetic properties of single-crystalline samples of a praseodymium-based cubic compound PrMgNi 4 were studied. The single-crystal X-ray structural analysis revealed that Mg atoms are substituted for the Pr atoms at the 4a site by 4.5%. The χ(T ) data follow the Curie-Weiss law with an effective moment for the Pr 3+ ion. The magnetic specific heat divided by temperature, C m /T , shows a broad maximum at around 3 K, which is reproduced by a two-level model with a ground state doublet. On cooling below 1 K, C m /T approaches a constant value, which behavior is reproduced by a random two-level model. The twofold degeneracy of the ground state is lifted by symmetry lowering due to the substituted Mg atoms for the Pr atoms or strong hybridizations between the 4 f 2 electron states and conduction bands, which hinders the long-range quadrupole order.Praseodymium-based cubic compounds with a 4 f 2 configuration have attracted much attention because a variety of phenomena manifest themselves at low temperatures. Pr-filled skutterudites exhibit correlated electronic phenomena due to strong hybridization between the 4 f electron and conduction electrons (cf hybridization), e.g., heavy-fermion superconductivity, a metal-insulator transition, and higher-order multipolar ordering.[1-4] These phenomena are attributed to the interplay between the conduction electrons and multipolar degrees of freedom in quasi-degenerated ground states of the Pr ions under the crystalline electric field (CEF).In case the CEF ground state is the non-Kramers doublet of the Pr ion under cubic symmetry, the magnetic dipole is quenched but electric quadrupole and magnetic octupole become active. Thereby, the multipoles in the non-Kramers doublet could govern the low-temperature properties. A typical system is PrPb 3 , which exhibits an antiferroquadrupole (AFQ) order at T Q = 0.4 K [5][6][7]. Below T Q , the quadrupoles are modulated sinusoidally by the correlation between the quadrupoles and the conduction electrons [8,9]. Another example is PrInNi 4 , which presents a ferromagnetic transition at T C = 0.75 K.[10-12] The nonmagnetic ground state doublet could mix with the excited magnetic triplet by the ferromagnetic exchange interaction inducing a magnetic moment in the ground state which orders ferromagnetically.On the contrary, PrAg 2 In and PrMg 3 exhibit no quadrupole order. [13][14][15] The absence of the quadrupole order was discussed by considering the Kondo effect due to strong c-f hybridization, because the specific heat divided by temperature, C/T , is largely enhanced at low temperatures. However, the thermoelectric power is not enhanced and the absolute value is comparable to that of the La counterpart, indicating the conduction electrons at the Fermi level could not correlate strongly with the 4 f 2 electrons. [16,17] Moreover, in the specific heat measurements using a high-quality single crystal of PrAg 2 In with the residual resistivity ratio of RRR = 14, a cusp-type anomaly manifests itself at 0.33 K, indic...

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A new ternary magnetically ordered heavy fermion compound Pr₂Rh₃Ge: magnetic, electronic and thermodynamic properties

Falkowski¹,

Strydom²

2017

J. Phys.: Condens. Matter

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The results of the magnetic, electron transport, heat capacity and heat conduction measurements on the new rhombohedral ternary compound PrRhGe have been investigated. The synthesized polycrystalline compound was found to crystallize in the ternary ordered variant of the cubic Laves phase [Formula: see text]-type of structure with the space group R[Formula: see text]m, as previously reported. PrRhGe exhibits a ferromagnetic behaviour below [Formula: see text] K, which was found to be unstable in low applied magnetic fields, revealing characteristics usually attributed to the long-range order. In the entire paramagnetic region electrical resistivity shows monotonous metallic conductivity character. We estimated that the Sommerfeld coefficient γ = 315 mJ/Pr-mol · [Formula: see text] of [Formula: see text] [Formula: see text]Ge is very large with comparison to ordinary metals which indicate the existence of heavy fermion behaviour of itinerant charge carriers at low temperatures or enhanced density of the quasi-particle state at the Fermi level. The crucial role of the crystalline electric field effects on the ground state properties of [Formula: see text] (J = 4) has been also observed. We think that the heavy fermion behaviour in [Formula: see text] [Formula: see text]Ge results from the dynamic low-lying crystal-field fluctuations, since there is no sign of Kondo effect in electrical resistivity and no enhancement of the slope S(T)/T in thermoelectric power data at low temperatures. It suggests that the conduction electrons at the Fermi level does not correlate with the 4f states of [Formula: see text] atoms and hence there is no place for a typical spin Kondo effect, as it is commonly observed in Ce- and Yb-based heavy fermion systems.

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Non-enhancement of thermoelectric-power coefficient of at low temperatures

Cited by 6 publications

References 10 publications

Heavy-electron-like behavior in cubic PrCu₄Au

Heavy-electron-like behavior in cubic PrCu₄Au

Hindered Quadrupole Order in PrMgNi₄ with a Nonmagnetic Doublet Ground State

A new ternary magnetically ordered heavy fermion compound Pr₂Rh₃Ge: magnetic, electronic and thermodynamic properties

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Non-enhancement of thermoelectric-power coefficient of at low temperatures

Cited by 6 publications

References 10 publications

Heavy-electron-like behavior in cubic PrCu4Au

Heavy-electron-like behavior in cubic PrCu4Au

Hindered Quadrupole Order in PrMgNi4 with a Nonmagnetic Doublet Ground State

A new ternary magnetically ordered heavy fermion compound Pr2Rh3Ge: magnetic, electronic and thermodynamic properties

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Product

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Heavy-electron-like behavior in cubic PrCu₄Au

Heavy-electron-like behavior in cubic PrCu₄Au

Hindered Quadrupole Order in PrMgNi₄ with a Nonmagnetic Doublet Ground State

A new ternary magnetically ordered heavy fermion compound Pr₂Rh₃Ge: magnetic, electronic and thermodynamic properties