High Pressure Phase Diagram of the Non-centrosymmetric Antiferromagnet CeCoGe<sub>3</sub>

Knebel, G.; Aoki, Dai; Lapertot, G.; Salce, B.; Flouquet, J.; Kawai, Takazumi; Muranaka, Hiroshi; Settai, Rikio; Ōnuki, Yoshichika

doi:10.1143/jpsj.78.074714

Cited by 38 publications

(28 citation statements)

References 24 publications

(23 reference statements)

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“…16). The heat capacity jump (∆C) at the superconducting transition [72], CeIrSi 3 [75], CeCoGe 3 [77] and CeIrGe 3 [42]. T * in panel (a) denotes an anomaly observed in the resistivity and magneticsusceptibility measurements [39].…”

Section: Temperature-pressure Phase Diagrammentioning

confidence: 99%

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Non-centrosymmetric Heavy-Fermion Superconductors

Kimura

Bonalde

2012

Non-Centrosymmetric Superconductors

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In this chapter we discuss the physical properties of a particular family of non-centrosymmetric superconductors belonging to the class heavy-fermion compounds. This group includes the ferromagnet UIr and the antiferromagnets CeRhSi 3 , CeIrSi 3 , CeCoGe 3 , CeIrGe 3 and CePt 3 Si, of which all but CePt 3 Si become superconducting only under pressure. Each of these superconductors has intriguing and interesting properties. We first analyze CePt 3 Si, then review CeRhSi 3 , CeIrSi 3 , CeCoGe 3 and CeIrGe 3 , which are very similar to each other in their magnetic and electrical properties, and finally discuss UIr. For each material we discuss the crystal structure, magnetic order, occurrence of superconductivity, phase diagram, characteristic parameters, superconducting properties and pairing states. We present an overview of the similarities and differences between all these six compounds at the end. CePt 3 SiThe enormous interest in superconductors without inversion symmetry started with the discovery of superconductivity in the heavy-fermion compound CePt 3 Si [1], which exhibits long-range antiferromagnetic (AFM) order below the Neel temperature T N = 2.2 K and becomes superconducting at the critical temperature T c = 0.75 K. CePt 3 Si is the only known heavy-fermion (HF) compound without inversion symmetry that superconducts at ambient pressure, as opposed to the cases of CeIrSi 3 , CeRhSi 3 , CeCoGe 3 , CeIrGe 3 and UIr. The heavy-fermion character has

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Section: Temperature-pressure Phase Diagrammentioning

confidence: 99%

“…a at 2.85 GPa b at 2.6 GPa c at 2.65 GPa d determined from heat-capacity measurements [77]. e determined from electrical-resistivity measurements [43].…”

Section: Quantum Criticality and Non-fermi Liquidmentioning

confidence: 99%

Non-centrosymmetric Heavy-Fermion Superconductors

Kimura

Bonalde

2012

Non-Centrosymmetric Superconductors

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“…The irreducible representation point group for the tetragonal structure of CePt 3 Si is C 4v , in which Rashba-type ASOC exists, which provides the key to understanding the intriguing superconducting behavior of CePt 3 Si [7][8][9]. Following CePt 3 Si many NCSs have been identified that present interesting superconducting properties, including Li 2 (Pd,Pt) 3 B [10,11], CeRhSi 3 [12,13], CeIrSi 3 [14], CeCoGe 3 [15,16], CeIrGe 3 [17], LaNiC 2 [18][19][20], BaPtSi 3 [21], (Rh,Ir)Ga 9 [22,23], Mg 10 Ir 19 B 16 [24], Mo 3 Al 2 C [25], LaRhSi 3 [26], Ca(Ir,Pt)Si 3 [27], Re 3 W [28], Nb 0.18 Re 0.12 [29], Re 6 Zr [30], La(Pd,Pt)Si 3 [31], Ca 3 Ir 4 Ge 4 [32], etc.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, like CePt 3 Si, a Rashba-type ASOC is present in these CeMX 3 compounds too, leading to an exotic superconducting ground state in them [12][13][14][15][16][17][33][34][35]. Like CePt 3 Si, they also exhibit heavy-fermion behavior and undergo a long-range antiferromagnetic ordering; however, they become superconducting only under the application of pressure [12][13][14][15][16][17][33][34][35]. The above-mentioned Ce-based NCSs are situated close to a magnetic quantum critical point, making it difficult to explore the effects of ASOC and inversion symmetry breaking on superconductivity.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of noncentrosymmetric superconductorLaIrSi3: AμSR study

et al. 2014

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The results of heat capacity C p (T ,H ) and electrical resistivity ρ(T ,H ) measurements down to 0.35 K as well as muon spin relaxation and rotation (μSR) measurements on the noncentrosymmetric superconductor LaIrSi 3 are presented. Powder neutron diffraction confirmed the reported noncentrosymmetric body-centered tetragonal BaNiSn 3 -type structure (space group I 4 mm) of LaIrSi 3 . The bulk superconductivity is observed below T c = 0.72(1) K. The intrinsic C e /γ n T c = 1.09(3) is significantly smaller than the BCS value of 1.43, and this reduction is accounted for by the α model of BCS superconductivity. The analysis of the superconducting-state C e (T ) data by the single-band α model indicates a moderately anisotropic order parameter with the s-wave gap (0)/k B T c = 1.54(2), which is lower than the BCS value of 1.764. Our estimates of various normal-and superconducting-state parameters indicate a weakly coupled electron-phonon-driven type-I s-wave superconductivity in LaIrSi 3 . The μSR results also confirm the conventional type-I superconductivity in LaIrSi 3 with a preserved time-reversal symmetry and hence a singlet pairing superconducting ground state.

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“…The high pressure phase diagram of CeCoGe 3 is quite complicated demonstrating six different phases. 13) Magnetic order vanishes around 55 kbar, and superconductivity is observed in the range of 54-75 kbar.…”

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confidence: 99%

High-Field de Haas–van Alphen Effect in Non-Centrosymmetric CeCoGe₃and LaCoGe₃

et al. 2011

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We report on de Haas-van Alphen effect measurements in the non-centrosymmetric systems CeCoGe 3 and LaCoGe 3 in magnetic field up to 28 Tesla. In both compounds, two new high frequencies were observed in high fields. The frequencies were not detected in previous lower field measurements. The frequencies do not originate from magnetic breakdown, and, therefore, are likely to be intrinsic features of the compounds. In CeCoGe 3 , the corresponding effective masses are strongly enhanced, being of the order of 30 bare electron masses.KEYWORDS: CeCoGe 3 , LaCoGe 3 , non-centrosymmetric, de Haas-van Alphen effectFollowing the discovery of superconductivity in the noncentrosymmetric heavy-fermion compound CePt 3 Si, 1) materials without inversion symmetry in their crystal structure have attracted a lot of experimental and theoretical interest. The interest is mainly due to a fascinating theoretical prediction 2, 3) that superconductive pairing in such systems requires an admixture of a spin-singlet with a spintriplet state. Subsequent observation of superconductivity in other non-centrosymmetric compounds CeRhSi 3 , 4) CeIrSi 3 , 5)CeCoGe 3 , 6, 7) and CeIrGe 3 8) has further stimulated the research efforts. Very unusual superconducting properties were indeed observed in some systems, such as enormously high upper critical field in CeIrSi 3 9) and CeRhSi 3 .10)The absence of inversion symmetry in the crystal lattice of a metal brings about a strong spin-orbit coupling, which in turn leads to the splitting of the electronic energy bands. The Fermi-surface of such a metal is, therefore, also split into two surfaces characterized by different chirality. This naturally results in the appearance of two distinct frequencies in the spectra of de Haas-van Alphen (dHvA) oscillations. It was demonstrated theoretically, 11) that the analysis of the oscillatory spectra in such materials provides a direct measure of the strength of the spin-orbit coupling. It is thus very important to obtain detailed and precise dHvA frequencies and their angular dependence in materials without inversion center. In most non-centrosymmetric compounds this coupling is extremely strong being of the order of 1000 K.CeCoGe 3 and its non-4 f analog LaCoGe 3 crystallize in the tetragonal BaNiSn 3 -type crystal structure. CeCoGe 3 is a moderate heavy-fermion system with a Sommerfeld coefficient of the specific heat γ = 0.032 J/molK 2 . It undergoes an untiferromagnetic transition at T N1 = 21 K, followed by two more transitions at T N2 = 12 K and T N3 = 8 K.12) Three consecutive metamagnetic transitions were observed for magnetic field applied along the easy magnetic c-axis. The high pressure phase diagram of CeCoGe 3 is quite complicated demonstrating six different phases.13) Magnetic order vanishes around 55 kbar, and superconductivity is observed in the range of 54-75 kbar.The dHvA effect in CeCoGe 3 and LaCoGe 3 was previ- *

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High Pressure Phase Diagram of the Non-centrosymmetric Antiferromagnet CeCoGe₃

Cited by 38 publications

References 24 publications

Non-centrosymmetric Heavy-Fermion Superconductors

Non-centrosymmetric Heavy-Fermion Superconductors

Physical properties of noncentrosymmetric superconductorLaIrSi3: AμSR study

High-Field de Haas–van Alphen Effect in Non-Centrosymmetric CeCoGe₃and LaCoGe₃

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High Pressure Phase Diagram of the Non-centrosymmetric Antiferromagnet CeCoGe3

Cited by 38 publications

References 24 publications

Non-centrosymmetric Heavy-Fermion Superconductors

Non-centrosymmetric Heavy-Fermion Superconductors

Physical properties of noncentrosymmetric superconductorLaIrSi3: AμSR study

High-Field de Haas–van Alphen Effect in Non-Centrosymmetric CeCoGe3and LaCoGe3

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Product

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High Pressure Phase Diagram of the Non-centrosymmetric Antiferromagnet CeCoGe₃

High-Field de Haas–van Alphen Effect in Non-Centrosymmetric CeCoGe₃and LaCoGe₃