Quadrupolar effect of R3Pd20Ge6 (R=Ce, Pr, Nd)

Horino, Takenobu; Сузукі, Осаму; Nemoto, Y.; Gotô, Terutaka; Dönni, A.; Nakayama, M.; Kimura, Noriaki; Tateiwa, Naoyuki; Aoki, H.; Komatsubara, T.

doi:10.1016/s0921-4526(99)01128-x

Cited by 3 publications

(3 citation statements)

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“…18,19) Previous ultrasonic measurements on Pr 3 Pd 20 Ge 6 showed a pronounced softening in the elastic constant C 44 down to 0.4 K, which is described in terms of the quadrupole susceptibility for the À 5 ground state system. 20) These experimental results imply that the magnetic À 5 triplet is a ground state for the CEF level scheme at the 4a site. The complete CEF level schemes at both sites 4a and 8c, and the nature of the quadrupole transitions in Pr 3 Pd 20 Ge 6 still remain to be solved.…”

Section: Introductionmentioning

confidence: 83%

Quadrupole Ordering and Rattling Motion of Clathrate Compound Pr₃Pd₂₀Ge₆

et al. 2012

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We have investigated the quadrupole ordering of 4f-electrons and the rattling motion of guest rare-earth ions in the clathrate compound Pr 3 Pd 20 Ge 6 using ultrasonic measurements. The elastic constants ðC 11 À C 12 Þ=2 and C 44 exhibit considerable softening at low temperatures. A minimum of ðC 11 À C 12 Þ=2 at T Q1 ¼ 0:25 K indicates antiferroquadrupole ordering associated with a À 3 doublet of a crystal-field ground state at the 8c site, while a minimum of C 44 at T Q2 ¼ 60 mK indicates the ferroquadrupole ordering of a À 5 triplet of a crystal-field ground state at the 4a site. The antiferroquadrupole phase depending on magnetic field direction shows a highly anisotropic behavior. The fieldinduced ordered phase due to the level crossing of the CEF ground state at the 8c site in magnetic fields along the [001] direction has been found. Furthermore, for the elastic constant C 44 and the attenuation coefficient 44 we found a frequency dependence at two different temperatures of 15 and 25 K, which we describe in terms of the Debye-type dispersion with an Arrhenius-type relaxation time ¼ 0 expðE=k B T Þ for two different activation energies of E L ¼ 102 K and E H ¼ 198 K. These ultrasonic dispersions are caused by the thermally activated rattling motions of guest rare-earth Pr 3þ ions at the 4a site of Pr 3 Pd 20 Ge 6 .

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Section: Introductionmentioning

confidence: 83%

Quadrupole Ordering and Rattling Motion of Clathrate Compound Pr₃Pd₂₀Ge₆

et al. 2012

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“…E-mail address: suzuki.osamu@nims.go.jp (O. Suzuki). [10]. Though the magnetic-and elastic properties at low temperature are not fully described by the CEF levels reported by the inelastic neutron scattering.…”

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confidence: 96%

“…Though the magnetic-and elastic properties at low temperature are not fully described by the CEF levels reported by the inelastic neutron scattering. For example the temperature dependence of the magnetic susceptibility below 2 K and the temperature dependence of elastic constant c 44 cannot be reproduced by 3 doublet ground state [9,10]. Therefore, to investigate the 4f-electronic ground state is main issue in this compound.…”

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confidence: 99%