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Lacroix, C.; Solontsov, A.; Ballou, R.

doi:10.1103/physrevb.54.15178

Cited by 35 publications

(19 citation statements)

References 19 publications

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“…Figure 3 and its inset show the 1/T 1 T versus T plots in CeIrIn 5 at P = 0, 1.0, 1.58 and 2.1 GPa and LaIrIn 5 at P = 0 GPa in linear and logarithmic scales, respectively. At P = 0 GPa, the T dependence of 1/T 1 T above T c is well explained by the anisotropic antiferromagnetic spin fluctuations model [4,12]. As seen in Fig.3, the application of pressure markedly suppresses the antiferromagnetic spin fluctuations, bringing the system away from the antiferromagnetic QCP.…”

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Enhancing the Superconducting Transition Temperature of the Heavy Fermion CompoundCeIrIn5in the Absence of Spin Correlations

et al. 2005

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We report on a pressure(P )-induced evolution of superconductivity and spin correlations in CeIrIn5 via the 115 In nuclear-spin-lattice-relaxation rate measurements. We find that applying pressure suppresses dramatically the antiferromagnetic fluctuations that are strong at ambient pressure. At P = 2.1 GPa, Tc increases to Tc = 0.8 K that is twice Tc(P = 0 GPa), in the background of Fermi liquid state. This is in sharp contrast with the previous case in which negative, chemical pressure (replacing Ir with Rh) enhances magnetic interaction and increases Tc. Our results suggest that multiple mechanisms work to produce superconductivity in the same compound CeIrIn5.The cerium (Ce)-based heavy-fermion compounds CeMIn 5 (M = Co, Rh, and Ir) discovered a few years ago provides a unique opportunity to investigate the interplay between antiferromagnetism and superconductivity [1,2,3]. Among CeMIn 5 , CeIrIn 5 and CeCoIn 5 show superconductivity at P = 0 below T c = 0.4 K and 2.3 K, respectively [2,3]. Antiferromagnet CeRhIn 5 becomes superconducting at relatively lower critical pressure P c ∼ 1.6 GPa and yet exhibits a higher T c ∼ 2 K [1]. Measurements of nuclear-quadrupole-resonance (NQR) [4,5,6,7], thermal transport and heat capacity [8] on CeMIn 5 found that the superconductivity is unconventional, with line-nodes in the superconducting gap function. NQR [4,5,7,9] and inelastic neutron diffraction [10] measurements also found strong antiferromagnetic spin fluctuations in the normal state. In addition, in CeIrIn 5 , the antiferromagnetic spin fluctuations are found to be anisotropic [4], namely, a magnetic correlation length ξ plane within the tetragonal plane grows up more dominantly than ξ c along the c-axis associated with their two-dimensional crystal structure. The nuclearspin-lattice-relaxation rate(1/T 1 ) was found to follow the relation of 1/T 1

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confidence: 63%

“…The same analysis was applied to CeCoIn 5 with resulting θ = 0.6 K [9,11]. Note that θ is a measure to what extent the system is close to an antiferromagnetic quantum critical point (QCP) [12]. It was suggested that the difference in the value of θ between CeIrIn 5 and CeCoIn 5 may lead to the large difference in the value of T c .…”

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Enhancing the Superconducting Transition Temperature of the Heavy Fermion CompoundCeIrIn5in the Absence of Spin Correlations

et al. 2005

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“…Let us now consider a situation where the dispersion of the SFs is in-between 2D and 3D ones. If the SF dispersion in one direction is flat, namely, the magnetic correlation length (ξ) is much shorter in one direction than in others, then by assuming χ(Q+q) −1 = χ −1 Q +a 1 (q 2 x +q 2 y )+a 2 q 4 z instead of isotropic quadratic dispersion [19], it is shown that 1/T 1 T ∝ χ 3/4…”

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Unique Spin Dynamics and Unconventional Superconductivity in the Layered Heavy Fermion CompoundCeIrIn5: NQR Evidence

et al. 2001

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We report measurements of the 115 In nuclear spin-lattice relaxation rate (1/T1) between T =0.09 K and 100 K in the new heavy fermion (HF) compound CeIrIn5. At 0.4 K ≤ T ≤ 100 K, 1/T1 is strongly T -dependent, which indicates that CeIrIn5 is much more itinerant than known Ce-based HFs. We find that 1/T1T , subtracting that for LaIrIn5, follows a ( 1 T +θ ) 3 4 variation with θ=8 K. We argue that this novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a magnetic ordering. The bulk superconductivity sets in at 0.40 K below which the coherence peak is absent and 1/T1 follows a T 3 variation, which suggests unconventional superconductivity with line-node gap. PACS: 74.25.Ha, 74.70Tx, 76.60.Gv The emergence of superconductivity near a magnetic instability in cerium (Ce)-based heavy fermion (HF) compounds is one of the most intriguing phenomena in strongly correlated electron systems. Except for CeCu 2 Si 2 which is superconducting at ambient pressure with T c =0. . In spite of efforts and progress, however, knowledge about this class of superconductors is still limited because of difficult experimental conditions. The recently discovered new family of Ce-based heavy electron systems, CeMIn 5 (M=Rh, Ir) with M=Ir being a superconductor already at ambient pressure [6,7], provides new opportunities for studying the nature of the superconductivity in the vicinity of a magnetic instability, the interplay between magnetic excitations and superconductivity, etc. In particular, CeIrIn 5 is suitable for studies using microscopic experimental probes that can be applied more easily at ambient pressure.CeMIn 5 (M=Rh, Ir) consists of alternating layers of CeIn 3 and MIn 2 . CeRhIn 5 is an antiferromagnet with T N =3.8 K but becomes superconducting below T c =2.1 K under pressures larger than 1.6 GPa [6]. In CeIrIn 5 , the resistivity is already zero at ambient pressure below 1.2 K, but the Meissner effect and the jump in the specific heat are found only at 0.4 K [7]. The electronic specific heat coefficient γ is found to be 750 mJ/mol K 2 [7], which suggests a large mass enhancement. Recent de Haas-van Alphen Oscillation in CeIrIn 5 also reveals a cyclotron mass that is ∼20 times larger than the band mass, consistent with the specific heat result [8].In this Letter, we report a measurement using local probe, the 115 In nuclear quadrupolar resonance (NQR) study in CeIrIn 5 down to 90 mK, at zero magnetic field.From the temperature (T ) dependence of the nuclear spin lattice relaxation rate (1/T 1 ), we find that CeIrIn 5 is much more itinerant than known Ce-compounds such as CeCu 2 Si 2 [9], and show that this compound is located near a magnetic ordering with anisotropic spin fluctuations due to the layered crystal structure. No anomaly was found at 1.2 K in the NQR quantities, but 1/T 1 shows an abrupt decrease at 0.40 K below which the NQR intensity also decreases as does the ac susceptibility, confirming a bulk superconductivity below T c =0.40 K. The lack of coherence peak in 1/T...

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“…The Mn spin correlation length is 2.86 Å, which is about the distance between the nearest Mn atoms along ͓110͔ direction, while is only 1.72 Å along the ͓001͔ direction. Lacroix et al 23 have developed an extended SCR theory to explain the low-T SF character found by the neutron experiment and predicted that 1/T 1 T should vary as Q 3/4 where Q is the staggered susceptibility at AF wave vector Q. One may think this prediction as a consequence of the decrease in the dimensionality, since in threedimensional ͑3D͒ systems 1/T 1 Tϰ Q 1/2 and in 2D systems 1/T 1 Tϰ Q , 3 In the case of strong AF spin fluctuation, 1/T 1 is dominated by Q , which follows the Curie-Weiss type T dependence, 3 therefore 1/T 1 Tϰ Q 3/4 ϰ1/(Tϩ) 3/4 .…”

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55MnNQR/NMR studies of the magnetic properties ofYMn2under pressure

et al. 1999

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We report magnetic properties of the antiferromagnet YMn 2 as functions of pressure and temperature ͑T͒ obtained from the 55 Mn spin-lattice relaxation rate and the Knight shift. An energy-band narrowing due to electron correlation is indicated by the Knight shift measurement and the application of pressure is found to enhance the conduction electron bandwidth. In the pressure-induced paramagnetic state, the system undergoes a crossover from an itinerant spin fluctuation ͑SF͒ regime at low T to a local SF regime at high T. It is pointed out that this magnetic crossover of SF resembles that of high-temperature superconductors.

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Spin fluctuations in itinerant electron antiferromagnetism and anomalous properties of Y(Sc)Mn2

Cited by 35 publications

References 19 publications

Enhancing the Superconducting Transition Temperature of the Heavy Fermion CompoundCeIrIn5in the Absence of Spin Correlations

Enhancing the Superconducting Transition Temperature of the Heavy Fermion CompoundCeIrIn5in the Absence of Spin Correlations

Unique Spin Dynamics and Unconventional Superconductivity in the Layered Heavy Fermion CompoundCeIrIn5: NQR Evidence

55MnNQR/NMR studies of the magnetic properties ofYMn2under pressure

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