Magnetic Phase Diagrams of Kondo Compounds Ce0.75La0.25B6and Ce0.6La0.4B6

Сузукі, Осаму; Gotô, Terutaka; Nakamura, Shintaro; Matsumura, T.; Kunii, S.

doi:10.1143/jpsj.67.4243

Cited by 94 publications

(87 citation statements)

References 23 publications

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“…6 The prediction of the accompanied lattice distortion along the [111] axis is indeed observed. 12 The model of the Γ 5u -type octupole order explains most of the characteristic behaviors in phase IV, 7 such as the cusp-like behavior in the uniform susceptibility, 9 no significant magnetic reflection in neutron scattering, 13 and the huge softening of C 44 mode in the strain susceptibility 14 as well as the spontaneous lattice distortion along [111]. 12 However, there has been no direct evidence from diffraction experiment.…”

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confidence: 99%

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Kusunose

Kuramoto

2005

J. Phys. Soc. Jpn.

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The azimuthal angle dependence observed in the resonant X-ray scattering in phase IV of Ce 0.7 La 0.3 B 6 is analyzed theoretically. It is shown that the peculiar angle dependence observed in the E2 channel is consistent with the Γ 5u -type octupole order with principal axis along (111) and equivalent directions. Under the assumption that the four equivalent octupole domains are nearly equally populated in the sample, the observed angle dependences are reproduced by calculation for both σσ ′ and σπ ′ polarizations. The calculation for various symmetries of order parameters excludes unambiguously other order parameters than the Γ 5u -type octupole. and Ce x La 1−x B 6 . [5][6][7] In particular, Ce x La 1−x B 6 exhibits a rich variety of the H-T phase diagram, called I-IV. 8,9 The importance of the octupole degrees of freedom was first recognized by Sakai and co-workers 10,11 in resolving the inconsistency between NMR and the neutron scattering measurements in the antiferro-quadrupole phase II. Soon after their work, possible relevance of the Γ 5u -type octupole to the magnetic phase III and III' was pointed out. 6 For consistent understanding of the overall phase diagram, this type of octupole was also suggested as a hidden order parameter of phase IV. 6 The prediction of the accompanied lattice distortion along the [111] axis is indeed observed. KEYWORDS12 The model of the Γ 5u -type octupole order explains most of the characteristic behaviors in phase IV, 7 such as the cusp-like behavior in the uniform susceptibility, 9 no significant magnetic reflection in neutron scattering, 13 and the huge softening of C 44 mode in the strain susceptibility 14 as well as the spontaneous lattice distortion along [111].12 However, there has been no direct evidence from diffraction experiment.Resonant X-ray scattering (RXS) measurement has been performed recently to obtain a direct evidence of the order parameter symmetry in phase IV. 19 The RXS has already proven its efficiency in various systems such as LaMnO 3 , 15 DyB 2 C 2 16-18 and NpO 2 . 2, 3 The measurement was done for Ce 0.7 La 0.3 B 6 below T IV = 1.5 K, using the L 2 absorption edge in the Ce atom. 19 They measured the azimuthal angle dependences of the superlattice Bragg reflections at q = (3/2, 3/2, 3/2) with the rotation axis normal to the [111] surface. Both the non-rotated (σ-σ ′ ), and the rotated (σ-π ′ ) polarization channels have been measured at the electric quadrupole (E2) resonance. In the σ-σ ′ channel, the scattering intensity exhibits six-fold oscillation, which indicates the occurrence of the electronic order with three-fold symmetry along [111]. In contrast, the σ-π ′ channel shows three-fold oscillation, which remains to be clarified. It is not clear to us how the fitting in ref.19 is justfied microscopically.In this Letter, we demonstrate that the Γ 5u -type octupole order can reproduce the azimuthal angle dependences both in the σ-σ ′ and σ-π ′ channels. The three-fold oscillation is explained in terms of domains whose principal axis is other ...

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confidence: 99%

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Kusunose

Kuramoto

2005

J. Phys. Soc. Jpn.

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“…This indicates that a Curie-like magnetic susceptibility must be observed at low temperatures in phase IV. However, below 1.4 K, at least down to 0.5 K, the Curie-like behavior due to the Nd ions is not observed in Ce 0.7 Nd 0.005 La 0.295 B 6 . 16 In addition, we also found the possible existence of some relationship between the * E-mail address: akihiro-kondo@hiroshima-u.ac.jp order parameters of phase IV and III.…”

Section: Introductionmentioning

confidence: 92%

“…2 In the course of the study of Ce x La 1−x B 6 , a new longrange-ordered (LRO) phase called phase IV which exists for x < 0.8, was discovered. [5][6][7] Phase IV exhibits the following characteristic features: a peak of the magnetic susceptibility at the IV-I transition temperature T I−IV , 5 a large elastic softening of C 44 within phase IV, 6 a small magnetic field dependence of the magnetoresistance in phase IV. 7 At present, a strong candidate for the LRO in phase IV is said to be Γ 5u -type AF octupole (AFO) order proposed by Kubo and Kuramoto.…”

Section: Introductionmentioning

confidence: 99%

Suppression of Phase IV in Ce_xLa_1-xB₆by R-Ion Doping

et al. 2008

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We have studied the effect of Nd doping on phase IV of Ce0.65NdyLa0.35−yB6 (y = 0.03, and 0.05) and Ce0.6Nd0.05La0.35B6 to obtain the information on the order parameter in phase IV. The suppression of phase IV by Nd doping is not so large for x ≤ 0.65 different from the rapid suppression of phase IV for x = 0.7. Based on these results, we discuss the importance of the different distance dependence of Oxy-AFQ, Txyz-AFO, AF exchange and the interaction forming phase IV in CexLa1−xB6.KEYWORDS: CexLa1−xB6, phase IV, hidden order, octupole order, multipole interaction IntroductionMultipole ordering is one of the recent topics in felectron systems. CeB 6 is well known for exhibiting multipole ordering and has been studied intensively.1-4 CeB 6 shows the antiferro-quadrupole (AFQ) order at T Q = 3.3 K and the antiferro (AF) magnetic order at T N = 2.3 K. These two phases are called phases II and III, respectively. The paramagnetic phase is called phase I. It is the first compound in which the crucial role of the octupole interaction in the unusual AFQ ordered phase of this compound was verified.

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“…26,27 These features are analogous to those in the phase IV of Ce 1−x La x B 6 with x ∼ 0.7, where the antiferro octupole order has been proposed, 28,29 and confirmed by various measurements. [30][31][32] The cubic symmetry in Ce 1−x La x B 6 allows pure octupoles which should have zero internal field at the Ce nucleus site, but with finite off-center field which has recently be detected by neutron scattering.…”

Section: Bilinear Coupling Of Dipoles and Octupoles In Smru 4 P 12mentioning

confidence: 99%

Toward Identification of Order Parameters in Skutterudites –a Wonderland of Strong Correlation Physics–

Kuramoto

Kiss

2008

J. Phys. Soc. Jpn.

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Current status is described toward identifying unconventional order parameters in filled skutterudites with unique ordering phenomena. The order parameters in PrFe 4 P 12 and PrRu 4 P 12 are discussed in relation to associated crystalline electric field (CEF) states and angular form factors. By phenomenological Landau analysis, it is shown that a scalar order model explains most properties in both PrFe 4 P 12 and PrRu 4 P 12 with very different magnetic properties. In particular, the highly anisotropic susceptibility induced by uniaxial pressure in PrFe 4 P 12 is explained in terms of two types of couplings. In the case of SmRu 4 P 12 , the main order parameter at low field is identified as magnetic octupoles. A microscopic mechanism is proposed how the dipole and octupole degrees of freedom mix under the point group T h of skutterudites.

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Magnetic Phase Diagrams of Kondo Compounds Ce_0.75La_0.25B₆and Ce_0.6La_0.4B₆

Cited by 94 publications

References 23 publications

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Suppression of Phase IV in Ce_xLa_1-xB₆by R-Ion Doping

Toward Identification of Order Parameters in Skutterudites –a Wonderland of Strong Correlation Physics–

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Magnetic Phase Diagrams of Kondo Compounds Ce0.75La0.25B6and Ce0.6La0.4B6

Cited by 94 publications

References 23 publications

Evidence for Octupole Order in Ce0.7La0.3B6 from Resonant X-ray Scattering

Evidence for Octupole Order in Ce0.7La0.3B6 from Resonant X-ray Scattering

Suppression of Phase IV in CexLa1-xB6by R-Ion Doping

Toward Identification of Order Parameters in Skutterudites –a Wonderland of Strong Correlation Physics–

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Magnetic Phase Diagrams of Kondo Compounds Ce_0.75La_0.25B₆and Ce_0.6La_0.4B₆

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Evidence for Octupole Order in Ce_0.7La_0.3B₆ from Resonant X-ray Scattering

Suppression of Phase IV in Ce_xLa_1-xB₆by R-Ion Doping