469 citations · 3.1k across the 37 of their papers we have counts for
28 papers · 1 filter
Thickness-induced crossover from strong to weak collective pinning in exfoliated FeTeSe thin films at 1 T
Ryoya Nakamura, Masashi Tokuda, Mori Watanabe +3
We studied flux pinning in exfoliated FeTeSe thin-film devices with a thickness from 30 to 150 nm by measuring the critical current density . In…
Negative correlation between the linear and the nonlinear conductance in magnetic tunnel junctions
Shuichi Iwakiri, Satoshi Sugimoto, Yasuhiro Niimi +4
The current-voltage () characteristics beyond the linear response regime of magnetic tunnel junction (MTJ) is systematically investigated. We find a clear negative correlation…
Spin treacle in a frustrated magnet observed with spin current
Hiroki Taniguchi, Mori Watanabe, Takashi Ibe +8
By means of spin current, the flow of spin angular momentum, we find a regime of "spin treacle" in a frustrated magnetic system. To establish its existence, we have performed spin…
Negative resistance state in superconducting NbSe induced by surface acoustic waves
Masahiko Yokoi, Satoshi Fujiwara, Tomoya Kawamura +5
We report a negative resistance, namely, a voltage drop along the opposite direction of a current flow, in the superconducting gap of NbSe thin films under the irradiation of s…
Butterfly-shaped magnetoresistance in triangular-lattice antiferromagnet AgCrO
Hiroki Taniguchi, Mori Watanabe, Masashi Tokuda +8
Spintronic devices using antiferromagnets (AFMs) are promising candidates for future applications. Recently, many interesting physical properties have been reported with AFM-based…
Quantum oscillations with magnetic hysteresis observed in CeTe thin films
Mori Watanabe, Sanghyun Lee, Takuya Asano +7
We have performed magnetotransport measurements in CeTe thin films down to . It is known that CeTe has two magnetic transitions at $T_{\rm N1} \approx 3~{\…
Etching process of narrow wire and application to tunable-barrier electron pump
Shota Norimoto, Shuichi Iwakiri, Masahiko Yokoi +3
Single electron sources have been studied as a device to establish an electric current standard for 30 years and recently as an on-demand coherent source for Fermion quantum optics…
Generation of Multipeak Spectrum of Spin Torque Oscillator in Non-linear Regime
Shuichi Iwakiri, Satoshi Sugimoto, Yasuhiro Niimi +4
We investigate the spectral characteristics of spin torque oscillator (STO) excited by the spin Hall-induced spin current. We observe that the modest spin current injection trigger…
Relation between spin Hall effect and anomalous Hall effect in 3 ferromagnetic metals
Yasutomo Omori, Edurne Sagasta, Yasuhiro Niimi +4
We study the mechanisms of the spin Hall effect (SHE) and anomalous Hall effect (AHE) in 3 ferromagnetic metals (Fe, Co, permalloy (NiFe; Py), and Ni) by varying t…
Dynamics of Pure Spin Current in High-frequency Quantum Regime
Shuichi Iwakiri, Yasuhiro Niimi, Kensuke Kobayashi
Pure spin current is a powerful tool for manipulating spintronic devices, and its dynamical behavior is an important issue. By using mesoscopic transport theory for electron tunnel…
Large room temperature spin-to-charge conversion signals in a few-layer graphene/Pt lateral heterostructure
Wenjing Yan, Edurne Sagasta, Mário Ribeiro +3
Electrical generation and detection of pure spin currents without the need of magnetic materials are key elements for the realization of full electrically controlled spintronic dev…
Tuning the spin Hall effect of Pt from the moderately dirty to the superclean regime
Edurne Sagasta, Yasutomo Omori, Miren Isasa +5
We systematically measure and analyze the spin diffusion length and the spin Hall effect in Pt with a wide range of conductivities using the spin absorption method in lateral spin…
Strong Suppression of the Spin Hall Effect in the Spin Glass State
Y. Niimi, M. Kimata, Y. Omori +5
We have measured spin Hall effects in spin glass metals, CuMnBi alloys, with the spin absorption method in the lateral spin valve structure. Far above the spin glass temperature Tg…
Reciprocal spin Hall effects in conductors with strong spin-orbit coupling: a review
Yasuhiro Niimi, YoshiChika Otani
Spin Hall effect and its inverse provide essential means to convert charge to spin currents and vice versa, which serve as a primary function for spintronic phenomena such as the s…
Inverse spin Hall effect in a closed loop circuit
Y. Omori, F. Auvray, T. Wakamura +3
We present measurements of inverse spin Hall effects (ISHEs) in which the conversion of a spin current into a charge current via the ISHE is detected not as a voltage in a standard…
Extrinsic spin Hall effects measured with lateral spin valve structures
Y. Niimi, H. Suzuki, Y. Kawanishi +4
The spin Hall effect (SHE), induced by spin-orbit interaction in nonmagnetic materials, is one of the promising phenomena for conversion between charge and spin currents in spintro…
5d transition metal oxide IrO2 as a material for spin current detection
Kohei Fujiwara, Yasuhiro Fukuma, Jobu Matsuno +4
Devices based on a pure spin current (a flow of spin angular momentum) have been attracting increasing attention as key ingredients for low-dissipation electronics. To integrate su…
Experimental Verification of Comparability between Spin-Orbit and Spin-Diffusion Lengths
Yasuhiro Niimi, Dahai Wei, Hiroshi Idzuchi +3
We experimentally confirmed that the spin-orbit lengths of noble metals obtained from weak anti-localization measurements are comparable to the spin diffusion lengths determined fr…
The spin Hall effect as a probe of nonlinear spin fluctuations
D. H. Wei, Y. Niimi, B. Gu +3
The spin Hall effect and its inverse play key roles in spintronic devices since they allow conversion of charge currents to and from spin currents. The conversion efficiency strong…
Giant Spin Hall Effect Induced by Skew Scattering from Bismuth Impurities inside Thin Film CuBi Alloys
Y. Niimi, Y. Kawanishi, D. H. Wei +6
We demonstrate that a giant spin Hall effect (SHE) can be induced by introducing a small amount of Bi impurities in Cu. Our analysis based on a new 3-dimensional finite element tre…
Extrinsic Spin Hall Effect Induced by Iridium Impurities in Copper
Y. Niimi, M. Morota, D. H. Wei +5
We study the extrinsic spin Hall effect induced by Ir impurities in Cu by injecting a pure spin current into a CuIr wire from a lateral spin valve structure. While no spin Hall eff…
Indication of intrinsic spin Hall effect in 4d and 5d transition metals
M. Morota, Y. Niimi, K. Ohnishi +4
We have investigated spin Hall effects in 4 and 5 transition metals, Nb, Ta, Mo, Pd and Pt, by incorporating the spin absorption method in the lateral spin valve structure; w…
Quantum Coherence at Low Temperatures in Mesoscopic Systems: Effect of Disorder
Yasuhiro Niimi, Yannick Baines, Thibaut Capron +6
We study the disorder dependence of the phase coherence time of quasi one-dimensional wires and two-dimensional (2D) Hall bars fabricated from a high mobility GaAs/AlGaAs heterostr…
Localized Distributions of Quasi Two-Dimensional Electronic States near Defects Artificially Created at Graphite Surfaces in Magnetic Fields
Y. Niimi, H. Kambara, Hiroshi Fukuyama
We measured the local density of states of a quasi two-dimensional electron system (2DES) near defects, artificially created by Ar-ion sputtering, on surfaces of highly oriented py…