Detection of Neutron Scattering from Phase IV of Ce0.7La0.3B6: A Confirmation of the Octupole Order

Kuwahara, K.; Iwasa, Kazuaki; Kohgi, M.; Aso, Naofumi; Sera, Masafumi; Iga, Fumitoshi

doi:10.1143/jpsj.76.093702

Cited by 69 publications

(52 citation statements)

References 23 publications

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“…Lanthanum doping of CeB 6 suppresses both AFM and AFQ phases and induces a new multipolar-ordered phase IV beyond a quantum critical point (QCP) at x ≈ 0.3, presumably of octupolar character [57][58][59]. Non-Fermi-liquid behavior has been observed in the vicinity of the QCP [60], and a recent specific-heat investigation of substituted Ce 1−x La x B 6 emphasizes the importance of multipolar fluctuations that are directly linked to the effective mass of charge carriers [61].…”

Section: Introductionmentioning

confidence: 99%

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
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We investigate the doping-induced changes in the electronic structure of CeB 6 on a series of substituted Ce 1−x R x B 6 samples (R = La, Nd) using diffuse neutron scattering. We observe a redistribution of magnetic spectral weight across the Brillouin zone, which we associate with the changes in the Fermi-surface nesting properties related to the modified charge carrier concentration. In particular, a strong diffuse peak at the corner of the Brillouin zone (R point), which coincides with the propagation vector of the elusive antiferroquadrupolar (AFQ) order in CeB 6 , is rapidly suppressed by both La and Nd doping, like the AFQ order itself. The corresponding spectral weight is transferred to the X (00 1 2 ) point, ultimately stabilizing a long-range AFM order at this wave vector at the Nd-rich side of the phase diagram. At an intermediate Nd concentration, a broad diffuse peak with multiple local maxima of intensity is observed around the X point, evidencing itinerant frustration that gives rise to multiple ordered phases for which Ce 1−x Nd x B 6 is known. On the La-rich side of the phase diagram, however, dilution of the magnetic moments prevents the formation of a similar (00 1 2 )-type order despite the presence of nesting. Our results demonstrate how diffuse neutron scattering can be used to probe the nesting vectors in complex f-electron systems directly, without reference to the single-particle band structure, and emphasize the role of Fermi surface geometry in stabilizing magnetic order in rare-earth hexaborides.

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Section: Introductionmentioning

confidence: 99%

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
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“…2. It is remarkable that the magnon is more intense around the Γ (110) point than at the equivalent Γ (001) or Γ (000) positions [49], suggesting an anomalous nonmonotonic behavior of the dynamic form factor that is characteristic of multipolar moments (for conventional dipolar moments, it would decrease monotonically with |Q|) [50][51][52]. A magnetic field of 2.5 T [ Fig.…”

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confidence: 99%

Magnetic field dependence of the neutron spin resonance inCeB6

et al. 2016

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In zero magnetic field, the famous neutron spin resonance in the f-electron superconductor CeCoIn 5 is similar to the recently discovered exciton peak in the nonsuperconducting CeB 6 . A magnetic field splits the resonance in CeCoIn 5 into two components, indicating that it is a doublet. Here we employ inelastic neutron scattering (INS) to scrutinize the field dependence of spin fluctuations in CeB 6 . The exciton shows a markedly different behavior without any field splitting. Instead, we observe a second field-induced magnon whose energy increases with field. At the ferromagnetic zone center, however, we find only a single mode with a nonmonotonic field dependence. At low fields, it is initially suppressed to zero together with the antiferromagnetic order parameter, but then reappears at higher fields inside the hidden-order phase, following the energy of an electron spin resonance (ESR). This is a unique example of a ferromagnetic resonance in a heavy-fermion metal seen by both ESR and INS consistently over a broad range of magnetic fields. PACS numbers: 71.27.+a, 76.50.+g, 78.70.Nx, 76.30.Kg INTRODUCTIONThe observation of neutron spin resonance within a broad range of materials, in particular high-T c cuprates [1], iron pnictides [2,3], and heavy-fermion superconductors [4][5][6], is recognized as an indicator of unconventional superconductivity. It was shown that sign-changing gap symmetry can lead to the existence of resonance behavior [7][8][9][10]. Of particular interest are inelastic neutron scattering (INS) results obtained on CeCoIn 5 , where a sharp resonance peak was observed within the superconducting phase [5,[11][12][13]. At first glance similar peaks were found in the antiferromagnetic (AFM) superconductor UPd 2 Al 3 [14,15], as well as in the normal state of the heavy-fermion metal YbRh 2 Si 2 [16], where superconductivity was recently discovered below ∼ 2 mK [17]. Another striking example of a resonant mode is given by the well known nonsuperconducting heavyfermion antiferromagnet CeB 6 [18,19]. The microscopic origins of such resonant magnetic excitations persisting in f-electron systems either with or without superconductivity may well differ among materials and are still hotly debated.The application of an external magnetic field may help to unmask the differences between these various excitations. For instance, among f-electron compounds, a weak quasielastic signal gives rise to a field-induced ferromagnetic (FM) excitation in CeRu 2 Si 2 [20]. In YbRh 2 Si 2 , two incommensurate excitation branches merge into a commensurate FM resonance whose energy scales linearly with magnetic field [16], whereas in UPd 2 Al 3 the energy gap initially remains almost constant inside the superconducting phase, but starts following a monotonic linear dependence at higher magnetic fields [14]. The sharp resonance in CeCoIn 5 splits into a Zeeman doublet [11] rather than a theoretically predicted triplet [21], whereas in Ce 1−x La x B 6 the magnetic field reportedly leads to a crossover from an itinerant to ...

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“…First, we have clarified the selection rules for the octupolar scattering on the basis of a symmetry analysis of the cross section. Then, we have discussed the magnetic form factor for phase IV of Ce 1−x La x B 6 , and have shown that a recent observation by Kuwahara et al 13) can be interpreted as the first example of the octupolar scattering. The possibility of observing the spectra for ordered octupoles in NpO 2 and field-induced octupoles in AFQ phases have been pointed out.…”

Section: Discussionmentioning

confidence: 95%

“…13) They reported that distinct magnetic Bragg peaks have been observed in the short wave-length region, although the existence of the peak at κ = (1/2, 1/2, 1/2) is not clear. The form factor at κ = (5/2, 5/2, 5/2) is estimated to be of about 0.1µ B per one Ce ion.…”

Section: )mentioning

confidence: 99%

Theory of Elastic Neutron Scattering by Ordered Magnetic Octupoles inf-Electron Systems

2008

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The symmetry property and characteristic momentum dependence of elastic neutron scattering spectra due to ordered magnetic octupoles in f -electron compounds are studied theoretically. In particular, it is shown through a form factor analysis of Ce1−xLaxB6 that a recent observation by Kuwahara et al. [J. Phys. Soc. Jpn. 76 (2007) 093702] is interpreted as a realization of such a novel scattering mechanism. A possible neutron scattering by field-induced octupoles in the quadrupolar phases is also discussed.

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Detection of Neutron Scattering from Phase IV of Ce_0.7La_0.3B₆: A Confirmation of the Octupole Order

Cited by 69 publications

References 23 publications

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
View full text Add to dashboard Cite

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
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Magnetic field dependence of the neutron spin resonance inCeB6

Theory of Elastic Neutron Scattering by Ordered Magnetic Octupoles inf-Electron Systems

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Detection of Neutron Scattering from Phase IV of Ce0.7La0.3B6: A Confirmation of the Octupole Order

Cited by 69 publications

References 23 publications

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and Nikitin1, Portnichenko2, Dukhnenko3 et al. 2018Phys. Rev. B123160View full textAdd to dashboardCite

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and Nikitin1, Portnichenko2, Dukhnenko3 et al. 2018Phys. Rev. B123160View full textAdd to dashboardCite

Magnetic field dependence of the neutron spin resonance inCeB6

Theory of Elastic Neutron Scattering by Ordered Magnetic Octupoles inf-Electron Systems

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Detection of Neutron Scattering from Phase IV of Ce_0.7La_0.3B₆: A Confirmation of the Octupole Order

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
View full text Add to dashboard Cite

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and
Nikitin
¹
,
Portnichenko
²
,
Dukhnenko
³

et al. 2018
Phys. Rev. B
12
3
16
0
View full text Add to dashboard Cite