Magnetic Structure Determination of CeT2Al10 (T = Ru and Os): Single Crystal Neutron Diffraction Studies

Kato, Hidemi; Kobayashi, Riki; Takesaka, Tomoaki; Nishioka, Takashi; Matsumura, Masatoshi; Kaneko, Koji; Metoki, Naoto

doi:10.1143/jpsj.80.073701

Cited by 78 publications

(73 citation statements)

References 14 publications

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“…After that, a neutron diffraction experiment using polycrystalline powder sample revealed that the transition is attributed to an antiferromgnetic order, and the Ce moment along the c-axis with a moment of 0.3µ B /Ce at 2 K [4]. This was confirmed by our neutron diffraction study using a single crystal, though the value of ordered moment is somewhat larger value of 0.42 µ B /Ce [5]. Up to now numerous experimental studies have been performed, but the reason of high transition temperature has not been clarified yet.…”

Section: Introductionsupporting

confidence: 75%

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Yokota¹,

Nishioka²,

Kitagawa³

et al. 2014

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013)

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Orthorhombic YbFe 2 Al 10 -type Kondo semiconductor CeT 2 Al 10 (T = Ru and Os) have anomalous high phase transition temperatures in spite of small Ce content. We have succeeded to synthesize new dilute rare earth hexagonal compounds Ce 2 Ru 3 Al 15 -type R 2 Ru 3 Al 15 (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) closely related to YbFe 2 Al 10 -type structure, and investigated their transport and magnetic properties. The electrical resistivity measurements indicate that all the compounds are metal, and R = Ce shows a logarithmic increase below 20 K due to Kondo effect. R = Ce, Nd, Sm, Gd, Tb, Dy, Ho and Er show antiferromagnetic transitions at T N = 3.5, 2.7, 9.2, 19.0, 15.7, 7.85, 3.0 and 1.6 K, respectively, and the T N almost follows the de Gennes' law except for R = Ce and Sm. R = Pr has nonmagnetic ground state and R = Tm is expected to order magnetically below 1.2 K from the susceptibility measurement. We have found that the Néel temperature of R = Ce is about 20 times larger than an expected value by the de Gennes' law, indicating that Ce 2 Ru 3 Al 15 is also a member of high magnetic transition temperature materials.

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Section: Introductionsupporting

confidence: 75%

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Yokota¹,

Nishioka²,

Kitagawa³

et al. 2014

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013)

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“…down to 1.6 K. These features suggest the electronic state near E F in the AF state is also influenced strongly by the changes in J cf and the impurity on the Al site. [14,16]. The anisotropic behavior of (T) for CeRu 2 Al 9.9 Ga 0.1 is also comparable to that for CeRu 2 Al 10 as shown in Fig.…”

Section: Ga Substitution Effectsupporting

confidence: 64%

“…Recently, the orthorhombic Kondo semiconductors CeT 2 Al 10 (T=Fe, Ru, and Os) have been studied intensively because the compounds with T=Ru and Os show an antiferromagnetic (AF) order with unusually high transition temperature T N =27 K and 28.5 K, respectively, in spite of the large nearest Ce-Ce distance (>5.2 Å) and reduced ordered moments ( AF =0.3-0.4  B ) [9][10][11][12][13][14][15][16]. In addition, T N exceeds that of isostructural GdT 2 Al 10 (T N =17.5 K for T=Ru and 18 K for T=Os) [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…The CEF analysis of the susceptibility and x-ray absorption spectra have revealed that the almost planar distribution of ground-state wave function of the 4f electrons is spread within the orthorhombic bc plane [19][20][21]. In the ordered state, however, the moment  AF aligns parallel to the c-axis [14,16]. As for this discrepancy of moment direction between the paramagnetic and AF states, anisotropic c-f hybridization between the ac plane and b direction is thought to play an important role from various studies such as optical conductivity and neutron scattering [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Ga and Si Substitutions for Al in CeRu₂Al₁₀ on the Unusual Antiferromagnetic Order in the Kondo Semiconducting State

Muro¹,

Hida²,

Fukuhara³

et al. 2014

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013)

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We have studied the effects of Ga and Si substitutions on the antiferromagnetic (AF) Kondo semiconductor CeRu 2 Al 10 which orders at rather high temperature T N = 27 K. In CeRu 2 Al 10-x Ga x , the semiconducting behavior is suppressed with increasing x up to x = 0.8. Thereby, T N is suppressed down to 24.5 K. The Si substitution changes the AF state more strongly. In fact, T N decreases to 23 K for CeRu 2 Al 9.9 Si 0.1 , probably due to the doping of 3p electrons. The magnetic susceptibility along the orthorhombic a-axis exhibits a sharp peak at T N below which those along the b-and c-axes do not decrease. This change can be explained by the reorientation of the ordered moments from the c-axis in CeRu 2 Al 10 to the a-axis in CeRu 2 Al 9.9 Si 0.1 . These findings indicate the importance of electron density for the unusual AF order in CeRu 2 Al 10 .

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“…An antiferromagnetic scenario, as originally proposed by one of the authors 1 based on magnetic and thermodynamic measurements, has been frequently argued to be incompatible with the large nearest neighbor distance between Ce ions, ∼ 5.2 A, and the de Gennes scaling of ordering temperatures of RRu 2 Al 10 (R = rare earth). µSR and neutron powder diffraction experiments have revealed a long-ranged, collinear antiferromagnetic ordering of the Ce sublattice below T 0 with, however, a strongly reduced magnetic moment of 0.34−0.42 µ B , and an unusual alignment along c axis that is not the magnetic easy direction 3,4 . The microscopic origin of the magnetic ordering, which apparently goes beyond the conventional Ruderman-KittelKasuya-Yosida (RKKY) interaction, remains elusive.…”

Section: Pacs Numbers: Valid Pacs Appear Herementioning

confidence: 99%

Magnetotransport properties of CeRu2Al10 : Similarities to URu2Si2

Zhang

Zhao

et al. 2016

Phys. Rev. B

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We report on magneto-transport properties of the Kondo semiconducting compound CeRu2Al10, focusing on its exotic phase below T0 = 27 K. In this phase, an excess thermal conductivity κ emerges and is gradually suppressed by magnetic field, strikingly resembling those observed in the hidden-order phase of URu2Si2. Our analysis indicates that low-energy magnetic excitation is the most likely origin, as was also proposed for URu2Si2 recently, despite the largely reduced magnetic moments. Likewise, other transport properties such as resistivity, thermopower and Nernst effect exhibit distinct features characterizing the very different charge dynamics above and below T0, sharing similarities to URu2Si2, too. Given the exotic nature of the ordered phases in both compounds, whether a unified interpretation to all these observations exists appears to be extremely interesting. PACS numbers: Valid PACS appear hereCeRu 2 Al 10 is one of the heavy-fermion (HF) materials showing timely interest due to a novel phase transition at an abnormally high temperature T 0 = 27 K emerging in a Kondo semiconducting phase 1,2 . An antiferromagnetic scenario, as originally proposed by one of the authors 1 based on magnetic and thermodynamic measurements, has been frequently argued to be incompatible with the large nearest neighbor distance between Ce ions, ∼ 5.2 A, and the de Gennes scaling of ordering temperatures of RRu 2 Al 10 (R = rare earth). µSR and neutron powder diffraction experiments have revealed a long-ranged, collinear antiferromagnetic ordering of the Ce sublattice below T 0 with, however, a strongly reduced magnetic moment of 0.34−0.42 µ B , and an unusual alignment along c axis that is not the magnetic easy direction 3,4 . The microscopic origin of the magnetic ordering, which apparently goes beyond the conventional Ruderman-KittelKasuya-Yosida (RKKY) interaction, remains elusive. On the other hand, transport properties of CeRu 2 Al 10 are intriguing as well. For instance, regardless of the formation of a partial gap over the majority of the Fermi surface with onset of the new phase, the electrical resistivity ρ(T ) ceases to be semiconducting-like and becomes metal-like upon cooling below T 0 . Moreover, both thermopower S(T ) and thermal conductivity κ(T ) are accompanied by an extra peak at temperatures slightly below T 0 or deep inside the ordered phase 1 .In this work, we investigate the magneto-transport properties of CeRu 2 Al 10 . Special attention is put on the excess thermal conductance emerging in the ordered phase below T 0 and its strong suppression upon applying magnetic field. Note that, strikingly similar behaviors have ever been observed for another heavy-fermion system, URu 2 Si 2 , in the hidden-order phase below T h = 17.5 K 5,6 . Enhanced phononic thermal conductance arising from a freezing out of relevant scattering centers below T h has been argued to be the origin 5,6 . This argument, however, is questionable in view of the strong field dependence and because of recent detailed experimental investiga...

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Magnetic Structure Determination of CeT₂Al₁₀ (T = Ru and Os): Single Crystal Neutron Diffraction Studies

Cited by 78 publications

References 14 publications

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Effects of Ga and Si Substitutions for Al in CeRu₂Al₁₀ on the Unusual Antiferromagnetic Order in the Kondo Semiconducting State

Magnetotransport properties of CeRu2Al10 : Similarities to URu2Si2

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Magnetic Structure Determination of CeT2Al10 (T = Ru and Os): Single Crystal Neutron Diffraction Studies

Cited by 78 publications

References 14 publications

Magnetic Properties of New Dilute Rare Earth Compounds R2Ru3Al15

Magnetic Properties of New Dilute Rare Earth Compounds R2Ru3Al15

Effects of Ga and Si Substitutions for Al in CeRu2Al10 on the Unusual Antiferromagnetic Order in the Kondo Semiconducting State

Magnetotransport properties of CeRu2Al10 : Similarities to URu2Si2

Contact Info

Product

Resources

About

Magnetic Structure Determination of CeT₂Al₁₀ (T = Ru and Os): Single Crystal Neutron Diffraction Studies

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Magnetic Properties of New Dilute Rare Earth Compounds R₂Ru₃Al₁₅

Effects of Ga and Si Substitutions for Al in CeRu₂Al₁₀ on the Unusual Antiferromagnetic Order in the Kondo Semiconducting State