Nuclear magnetic resonance in Kondo lattice systems

Curro, N. J.

doi:10.1088/0034-4885/79/6/064501

Cited by 12 publications

(9 citation statements)

References 40 publications

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“…We find no Knight shift anomaly at the 27 Al(4) site down to 5 K. This may be a consequence of the factor of three smaller hyperfine coupling at the 27 Al(4) as compared to 27 Al(3). It has been shown that the Knight shift anomaly nearly vanishes for H â in the Ce-115 systems [14]. So, it is probable that the anomaly is weak at the 27 Al(4) site for H ĉ and then vanishes for H â.…”

Section: Knight Shift Anomalymentioning

confidence: 99%

“…In uncorrelated paramagnetic compounds, we expect the Knight shift to be proportional to the bulk magnetic susceptibility [32]. In Kondo lattice heavy fermion systems, there is a ubiquitous observation of deviation from this proportionality that has come to be associated with the formation of the coherent heavy electron fluid below the coherence temperature T * [14]. In the discussion below, we follow the literature and refer to the entire shift as the Knight shift.…”

Section: Knight Shift Anomalymentioning

confidence: 99%

“…Here we present an NMR study of the spectral and dynamical properties of 59 Co and 27 Al in Ce 2 CoAl 7 Ge 4 . We have identified an NMR Knight shift (K) anomaly indicating the onset of coherence of the Kondo lattice below a characteristic temperature T * , below which the NMR Knight shift and the bulk magnetic susceptibility are no longer proportional [14]. We also measured the spinlattice relaxation rate (T −1 1 ) as a function of temperature.…”

Section: Introductionmentioning

confidence: 98%

“…The resulting NMR Knight shift and quadrupolar splitting of the satellite transitions allow for the identification of nonequivalent atomic sites and provide microscopic information. NMR has been shown to be a powerful probe of magnetism, superconductivity, and the normal state of heavy fermion materials [13,14].…”

Section: Introductionmentioning

confidence: 99%

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Nuclear magnetic resonance investigation of the heavy fermion system Ce2CoAl7Ge4

et al. 2017

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We present nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements performed on single crystalline Ce2CoAl7Ge4, a member of a recently discovered family of heavy fermion materials Ce2M Al7Ge4 (M = Co, Ir, Ni, or Pd). Previous measurements indicated a strong Kondo interaction as well as magnetic order below TM = 1.8 K. Our NMR spectral measurements show that the Knight shift K is proportional to the bulk magnetic susceptibility χ at high temperatures. A clear Knight shift anomaly (K ∝ χ) is observed at coherence temperatures T * ∼ 17.5 K for H0 ĉ and 10 K for H0 â at the 59 Co site, and T * ∼ 12.5 K at the 27 Al(3) site for H0 â characteristic of the heavy fermion nature of this compound. At high temperatures the 59 Co NMR spin-lattice relaxation rate T −1 1 is dominated by spin fluctuations of the 4f local moments with a weak metallic background. The spin fluctuations probed by 59 Co NMR are anisotropic and larger in the basal plane than in the c direction. Furthermore, we find (T1T K) −1 ∝ T −1/2 at the 59 Co site as expected for a Kondo system for T > T * and T > TK . 59 Co NQR T −1 1 measurements at low temperatures indicate slowing down of spin fluctuations above the magnetic ordering temperature TM ∼ 1.8 K. A weak ferromagnetic character of fluctuations around q = 0 is evidenced by an increase of χT versus T above the magnetic ordering temperature. We also find good agreement between the observed and calculated electric field gradients at all observed sites. 1 driven by local moment spin fluctuations agree well with the experimentally observed value. We also find that (T 1 T K) −1 ∝ T −1/2 at the 59 Co site as expected for a Kondo system at high temperatures relative to T * and T K [15]. At low temperatures, 59 Co arXiv:1812.08633v1 [cond-mat.str-el]

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Section: Knight Shift Anomalymentioning

confidence: 99%

Section: Knight Shift Anomalymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Nuclear magnetic resonance investigation of the heavy fermion system Ce2CoAl7Ge4

et al. 2017

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“…CeRhIn 5 presents a unique opportunity to tune a highly correlated system between a diverse set of ground states, including unconventional superconductivity, local-moment magnetism, a putative (spin-or charge-) nematic, and a heavy Fermi liquid 8,13,21,22 . Here we chart the unknown territory of combined high field/high pressure, to serve as a testbed for theoretical approaches tackling this problem.…”

mentioning

confidence: 99%

Non-monotonic pressure dependence of high-field nematicity and magnetism in CeRhIn5

et al. 2020

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CeRhIn 5 provides a textbook example of quantum criticality in a heavy fermion system: Pressure suppresses local-moment antiferromagnetic (AFM) order and induces superconductivity in a dome around the associated quantum critical point (QCP) near p c ≈ 23 kbar. Strong magnetic fields also suppress the AFM order at a field-induced QCP at B c ≈ 50 T. In its vicinity, a nematic phase at B * ≈ 28 T characterized by a large in-plane resistivity anisotropy emerges. Here, we directly investigate the interrelation between these phenomena via magnetoresistivity measurements under high pressure. As pressure increases, the nematic transition shifts to higher fields, until it vanishes just below p c. While pressure suppresses magnetic order in zero field as p c is approached, we find magnetism to strengthen under strong magnetic fields due to suppression of the Kondo effect. We reveal a strongly nonmean-field-like phase diagram, much richer than the common local-moment description of CeRhIn 5 would suggest.

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Orbitally defined field-induced electronic state in a Kondo lattice

et al. 2020

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CeRhIn5 is a Kondo-lattice prototype in which a magnetic field B * 30 T induces an abrupt Fermi-surface (FS) reconstruction 1,2 and pronounced in-plane electrical transport anisotropy 3 all within its antiferromagnetic state. Though the antiferromagnetic order at zero field is wellunderstood, the origin of an emergent state at B * remains unknown due to challenges inherent to probing states microscopically at high fields. Here, we report low-temperature Nuclear Magnetic Resonance (NMR) measurements revealing a discontinuous decrease in the 115 In formal Knight shift, without changes in crystal or magnetic structures, of CeRhIn5 at fields spanning B * . We discuss the emergent state above B * in terms of a change in Ce's 4f orbitals that arises from field-induced evolution of crystal-electric field (CEF) energy levels. This change in orbital character enhances hybridisation between the 4f and the conduction electrons (c.e.) that leads ultimately to an itinerant quantum-critical point at B c0 50 T. arXiv:1905.02861v2 [cond-mat.str-el]

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Nuclear magnetic resonance in Kondo lattice systems

Cited by 12 publications

References 40 publications

Nuclear magnetic resonance investigation of the heavy fermion system Ce2CoAl7Ge4

Nuclear magnetic resonance investigation of the heavy fermion system Ce2CoAl7Ge4

Non-monotonic pressure dependence of high-field nematicity and magnetism in CeRhIn5

Orbitally defined field-induced electronic state in a Kondo lattice

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