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Your search keyword '"Shiino, Takayuki"' showing total 23 results
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23 results on '"Shiino, Takayuki"'

1. Anomalous magnetic transition in a disordered quasicrystal approximant with heavy-fermion nature

Author

Shiino, Takayuki, Labib, Farid, Hirano, Yuma, Deguchi, Kazuhiko, Imura, Keiichiro, Sugimoto, Takanori, Ohhashi, Satoshi, Fujita, Nobuhisa, Tsai, An-Pang, and Sato, Noriaki K.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Quasicrystal approximant (CexY1-x)Cd6 (0 < x < 1) forms a network of corner-sharing octahedra. We report that (Ce0.8Y0.2)Cd6 exhibits an anomalous magnetic transition which can be classified neither into the conventional static magnetic ordering nor into spin glasses. The anomalous transition is characterized by the coexistence of a static order and a frequency-dependent sharp positive anomaly in the 3rd-harmonic susceptibility. Based on the investigation of the reference systems CeCd6 and (Ce0.05Y0.95)Cd6, we speculate that the anomalous transition could be induced by disorder in the possible frustrated Ce-network in the presence of the Kondo effect., Comment: 5 figures

Published
2024

3. Antiferromagnetic domain wall motion driven by spin-orbit torques

Author

Shiino, Takayuki, Oh, Se-Hyeok, Haney, Paul M., Lee, Seo-Won, Go, Gyungchoon, Park, Byong-Guk, and Lee, Kyung-Jin

Subjects
Condensed Matter - Materials Science
Abstract

We theoretically investigate dynamics of antiferromagnetic domain walls driven by spin-orbit torques in antiferromagnet/heavy metal bilayers. We show that spin-orbit torques drive antiferromagnetic domain walls much faster than ferromagnetic domain walls. As the domain wall velocity approaches the maximum spin-wave group velocity, the domain wall undergoes Lorentz contraction and emits spin-waves in the terahertz frequency range. The interplay between spin orbit torques and the relativistic dynamics of antiferromagnetic domain walls leads to the efficient manipulation of antiferromagnetic spin textures and paves the way for the generation of high frequency signals in antiferromagnets., Comment: 5 pages, 3 figures

Published
2016
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5. Effect of pseudo-Tsai cluster incorporation on the magnetic structures of R−Au−Si (R=Tb,Ho) quasicrystal approximants

Author

Gebresenbut, Girma Hailu, primary, Shiino, Takayuki, additional, Andersson, Mikael Svante, additional, Qureshi, Navid, additional, Fabelo, Oscar, additional, Beran, Premysl, additional, Qvarngård, Daniel, additional, Henelius, Patrik, additional, Rydh, Andreas, additional, Mathieu, Roland, additional, Nordblad, Per, additional, and Pay Gomez, Cesar, additional

Published
2022
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9. Effect of pseudo-Tsai cluster incorporation on the magnetic structures of R-Au-Si (R = Tb, Ho) quasicrystal approximants

Author

Gebresenbut, Girma Hailu, Shiino, Takayuki, Andersson, Mikael Svante, Qureshi, Navid, Fabelo, Oscar, Beran, Premysl, Qvarngard, Daniel, Henelius, Patrik, Rydh, Andreas, Mathieu, Roland, Nordblad, Per, and Pay Gómez, Cesar

Subjects
Condensed Matter Physics, Den kondenserade materiens fysik
Abstract

In cluster-based quasicrystals, tetrahedra located in conventional Tsai clusters may be replaced by single rare-earth (R) ions at the cluster centers (pseudo-Tsai clusters). In this study, we investigate the effect of the pseudo-Tsai cluster incorporation on the magnetic structures of two approximants, the Tsai-type Tb-Au-Si [denoted TAS(0)] and Ho-Au-Si [denoted HAS(52)] with partial replacement of conventional Tsai clusters by pseudo-Tsai clusters, up to 52%. The mixture of Tsai and pseudo-Tsai clusters can be considered a different source of randomness/disorder other than the conventional chemical mix sites (Au/Si). The effect of the latter has been previously discussed regarding the origin/cause of spin-glass-like ordering and Anderson localization of electronic states in quasicrystals and approximant crystals. Single crystal neutron diffraction experiments at 2 K were performed and bulk physical properties (magnetization and specific heat) were investigated. In addition, earlier collected powder neutron diffraction data of TAS(14) with 14% replacement was reanalyzed in light of the results on TAS(0) and HAS(52). We find that the arrangement of ordered magnetic spins in the icosahedral shells of these phases is similar, while the cluster-center R magnetic states are different. In the case of TAS(14), the cluster-center Tb magnetic moments seem to affect the arrangement of surrounding icosahedral magnetic moments, and the magnetic structure of the icosahedral shell deviates from that of TAS(0). In the case of HAS(52), however, the icosahedral R magnetic moments are less affected by the cluster-center R, while the averaged cluster-center R magnetic moments are significantly diminished. We discuss these results considering the magnetic ordering effect on the bulk physical properties.

Published
2022

18. Local Quantum Fluctuations in Kondo Quasicrystal Approximant Ag–In–(CexY1−x).

Author

Sawano, Takuya, Shiino, Takayuki, Imura, Keiichiro, Deguchi, Kazuhiko, Ohhashi, Satoshi, Tsai, An-Pang, and Sato, Noriaki K.

Abstract

The ternary alloy Ag–In–Ce is the only Ce-based quasicrystal approximant showing the heavy fermion feature. Here, we report the physical properties of Ag–In–(CexY1−x). As the Ce concentration x is diluted by the nonmagnetic element Y, the spin glass freezing temperature Tf is progressively suppressed. At T > Tf, the uniform magnetic susceptibility and electronic specific heat coefficient show \(\chi (T,x)^{ - 1} = \alpha [T^{\zeta } + \theta _{\text{eff}}^{\zeta }(x)]\) (where α is a constant, ζ \(\simeq \) 0.7, and θeff is an effective Weiss temperature) and \(C(T,x)/T = \beta \ln [T/T_{0}(x)]\) (where β is a constant and T0 is a characteristic temperature), respectively. Near the critical concentration xc where θeff vanishes, χ and C/T exhibit power-law and logarithmic divergence, respectively, as T → 0. We stress that α, ζ, and β are independent of x, indicating that the Tζ and ln T terms come from local fluctuations that are present everywhere in the x–T phase diagram, regardless of quantum critical point. We argue that the quantum critical behavior is driven by valence fluctuations. [ABSTRACT FROM AUTHOR]

Published
2020
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23. Superconducting YAu 3 Si and Antiferromagnetic GdAu 3 Si with an Interpenetrating Framework Structure Built from 16-Atom Polyhedra.

Author

Gebresenbut GH, Eriksson L, Häussermann U, Rydh A, Mathieu R, Vekilova OY, and Shiino T

Abstract

Investigations of reaction mixtures RE x (Au 0.79 Si 0.21 ) 100- x (RE = Y and Gd) yielded the compounds REAu 3 Si which adopt a new structure type, referred to as GdAu 3 Si structure ( tP 80, P 4 2 / mnm , Z = 16, a = 12.8244(6)/12.7702(2) Å, and c = 9.0883(8)/9.0456(2) Å for GdAu 3 Si/YAu 3 Si, respectively). REAu 3 Si was afforded as millimeter-sized faceted crystal specimens from solution growth employing melts with composition RE 18 (Au 0.79 Si 0.21 ) 82 . In the GdAu 3 Si structure, the Au and Si atoms are strictly ordered and form a framework built of corner-connected, Si-centered, trigonal prismatic units SiAu 6 . RE atoms distribute on 3 crystallographically different sites and each attain a 16-atom coordination by 12 Au and 4 Si atoms. These 16-atom polyhedra commonly fill the space of the unit cell. The physical properties of REAu 3 Si were investigated by heat capacity, electrical resistivity, and magnetometry techniques and are discussed in the light of theoretical predictions. YAu 3 Si exhibits superconductivity around 1 K, whereas GdAu 3 Si shows a complex magnetic ordering, likely related to frustrated antiferromagnets exhibiting chiral spin textures. GdAu 3 Si-type phases with interesting magnetic and transport properties may exist in an extended range of ternary RE-Au-Si systems, similar to the compositionally adjacent cubic 1/1 approximants RE(Au,Si) ∼6 .

Published
2022
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