Electron-spin-resonance investigation of the heavy-fermion compound<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Ce</mml:mi><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></m

Nidda, H.-A. Krug von; Schütz, A.; Heil, M.; Elschner, B.; Loidl, A.

doi:10.1103/physrevb.57.14344

Cited by 23 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The analysis of the spectra following ref. [11] results in low values for the uniaxial CEF-parameter 0.3 GHz < ∼ b 0 2 < ∼ 0.7 GHz, compared to the microwave frequency ν = 9 GHz. Hence, the influence of the crystal field can be neglected for all further discussion.…”

Section: A Esr Spectramentioning

confidence: 87%

“…If the exchange interaction is large compared to the crystal-field splitting, the different dipolar transitions are strongly coupled to each other, and the spectrum is exchange narrowed into a single ESR line with orientation dependent linewidth and resonance field. For a closer discussion of these effects refer to [11]. The spectra of all samples show only a weak dependence on the orientation.…”

Section: A Esr Spectramentioning

confidence: 96%

“…In heavyfermions (e.g. CeCu 2 Si 2 [10], CeNi 2 Ge 2 [11]) the Cespin fluctuations yield an additional contribution to the usual Korringa relaxation. In intermediate valent compounds (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

ESR experiments on the Kondo insulator CeNiSn

et al. 1999

Self Cite

View full text Add to dashboard Cite

Below a characteristic temperature, due to hybridisation effects Kondo insulators exhibit a gap in the electronic density of states and behave like semiconductors. By using Gd 3+ electron spin resonance (ESR), the compound CeNiSn was investigated as a representative of this class. In addition, the metal-to-insulator transition was studied as a function of doping for CeNi1−xCoxSn and CeNi1−yPtySn. The linewidth of the Gd resonance yields direct information about the density of states at the Fermi energy. So the size of the gap can clearly be estimated for the pure compound, and the closing of the gap by substitution of Ni by Co or Pt can be followed in detail. These results are compared to measurements of NMR, specific heat and susceptibility. 71.20.Eh, 71.27.+a, 72.15.Qm, 76.30.Kg

show abstract

Section: A Esr Spectramentioning

confidence: 87%

Section: A Esr Spectramentioning

confidence: 96%

See 1 more Smart Citation

ESR experiments on the Kondo insulator CeNiSn

et al. 1999

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the temperature evolution of the linewidth observed in Gd 1−x Sr x TiO 3 differs completely from the linear Korringa law [12], but it reveals similar features as the Gd ESR [11,13] and NMR spin-lattice relaxation rate [14] [4]. In all these systems a second important contribution to the spin-lattice relaxation arises from spin fluctuations of the electronic bath due to the fluctuation-dissipation theorem, which for temperatures large compared to the exciting frequency k B T ≫hω reads…”

mentioning

confidence: 87%

“…The evaluation of comparable Gd 3+ spectra has been described in detail in a previous publication [11]. Their intensity follows the CurieWeiss behavior of the static susceptibility measured with the SQUID magnetometer and comparison with a standard sample showed that it is due to all Gd 3+ spins.…”

mentioning

confidence: 99%

Heavy-fermion formation at the metal-to-insulator transition inGd1−xSrx
Heinrich
¹
,
Nidda
²
,
Fritsch
³

et al. 2001
Phys. Rev. B
Self Cite

View full text Add to dashboard Cite

The perovskite-like transition-metal oxide Gd1−xSrxTiO3 is investigated by measurements of resistivity, specific-heat, and electron paramagnetic resonance (EPR). Approaching the metal-toinsulator transition from the metallic regime (x ≥ 0.2), the Sommerfeld coefficient γ of the specific heat becomes strongly enhanced and the resistivity increases quadratically at low temperatures, which both are fingerprints of strong electronic correlations. The temperature dependence of the dynamic susceptibility, as determined from the Gd 3+ -EPR linewidth, signals the importance of strong spin fluctuations, as observed in heavy-fermion compounds. PACS: 71.30, 71.27, 76.30 The transition-metal oxides RTiO 3 (where R denotes Y 3+ , La 3+ , or some trivalent rare-earth ion) are known as typical Mott-Hubbard insulators with Ti 3+ in a 3d 1 electronic configuration [1]. Doping R 1−x A x TiO 3 with divalent alkali-earth ions A like Ca 2+ or Sr 2+ partially changes the Ti valence to Ti 4+ (3d 0 ) and induces metallic behavior at a certain doping concentration x. The metal-to-insulator transition of La 1−x Sr x TiO 3 and Y 1−x Ca x TiO 3 has been investigated in detail [2,3]. A critical increase of the Sommerfeld coefficient γ of the specific heat approaching the metal-to-insulator transition has been observed in both compounds with γ ≈ 25 mJ/(mole K 2 ) in Y 0.6 Ca 0.4 TiO 3 , indicating an enhancement of the effective electron mass. Heavy-fermion formation has been observed in a number of transitionmetal oxides, with Sr 1−x Ca x RuO 3 [4] and LiV 2 O 4 [5] being the most prominent examples. In the latter two compounds the temperature dependence of the dynamic susceptibility, as probed by the spin-lattice relaxation time in NMR experiments, played a key role in identifying the heavy-fermion behavior. In this letter we investigate the dynamic susceptibility utilizing Gd EPR and provide experimental evidence of heavy-fermion behavior in Gd 1−x Sr x TiO 3 .Ceramic samples of Gd 1−x Sr x TiO 3 have been calcinated from TiO 2 , SrCO 3 , Gd 2 O 3 and Ti 2 O 3 powders of high purity (better than 3N) and pressed into pellets. These pellets have been annealed at 1473 K under N 2 atmosphere for 15 hours and finally arc-melted under argon atmosphere. For Sr concentrations x ≤ 0.7 X-ray powder diffraction revealed the proper orthorhombically distorted GdFeO 3 perovskite structure [6]. For x > 0.7 the system attains the cubic perovskite structure like pure SrTiO 3 . The volume of the unit cell remains nearly constant at about 235Å 3 in the whole concentration range. Susceptibility measurements were performed with a commercial SQUID magnetometer (Quantum Design) in a temperature range 4.2 ≤ T ≤ 400 K. Pure GdTiO 3 shows a ferrimagnetic susceptibility, which follows a Curie-Weiss law χ ∝ (T + Θ) −1 with Θ = 10 K at high temperatures T > 100 K, and exhibits an ordering temperature T C ≈ 28 K. This fits reasonably to the value of 34 K given in literature [7], where the ordered state is reported to show an antiparallel alignment of the ferromagne...

show abstract

Microwave spectroscopy on heavy‐fermion systems: Probing the dynamics of charges and magnetic moments

Scheffler

Schlegel

Clauss

et al. 2013

Physica Status Solidi (b)

View full text Add to dashboard Cite

Investigating solids with light gives direct access to charge dynamics, electronic and magnetic excitations. For heavy fermions, one has to adjust the frequency of the probing light to the small characteristic energy scales, leading to spectroscopy with microwaves. We review general concepts of the frequency-dependent conductivity of heavy fermions, including the slow Drude relaxation and the transition to a superconducting state, which we also demonstrate with experimental data taken on UPd 2 Al 3 . We discuss the optical response of a Fermi liquid and how it might be observed in heavy fermions. Microwave studies with focus on quantum criticality in heavy fermions concern the charge response, but also the magnetic moments can be addressed via electron spin resonance (ESR). We discuss the case of YbRh 2 Si 2 , the open questions concerning ESR of heavy fermions, and how these might be addressed in the future. This includes an overview of the presently available experimental techniques for microwave studies on heavy fermions, with a focus on broadband studies using the Corbino approach and on planar superconducting resonators.

show abstract

Electron-spin-resonance investigation of the heavy-fermion compoundCe(Cu1−xNix

Cited by 23 publications

References 17 publications

ESR experiments on the Kondo insulator CeNiSn

ESR experiments on the Kondo insulator CeNiSn

Heavy-fermion formation at the metal-to-insulator transition inGd1−xSrx
Heinrich
¹
,
Nidda
²
,
Fritsch
³

et al. 2001
Phys. Rev. B
Self Cite

Microwave spectroscopy on heavy‐fermion systems: Probing the dynamics of charges and magnetic moments

Contact Info

Product

Resources

About

Electron-spin-resonance investigation of the heavy-fermion compoundCe(Cu1−xNix

Cited by 23 publications

References 17 publications

ESR experiments on the Kondo insulator CeNiSn

ESR experiments on the Kondo insulator CeNiSn

Heavy-fermion formation at the metal-to-insulator transition inGd1−xSrxHeinrich1, Nidda2, Fritsch3 et al. 2001Phys. Rev. BSelf Cite

Microwave spectroscopy on heavy‐fermion systems: Probing the dynamics of charges and magnetic moments

Contact Info

Product

Resources

About

Heavy-fermion formation at the metal-to-insulator transition inGd1−xSrx
Heinrich
¹
,
Nidda
²
,
Fritsch
³

et al. 2001
Phys. Rev. B
Self Cite