Refine your search:     
Report No.
Search Results: Records 1-7 displayed on this page of 7
  • 1

Presentation/Publication Type

Initialising ...


Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...


Initialising ...


Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Local bifurcation with spin-transfer torque in superparamagnetic tunnel junctions

Funatsu, Takuya*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*

Nature Communications (Internet), 13, p.4079_1 - 4079_8, 2022/07

 Times Cited Count:2 Percentile:78.71(Multidisciplinary Sciences)

Modulation of the energy landscape by external perturbations governs various thermally-activated phenomena, described by the Arrhenius law. Thermal fluctuation of nanoscale magnetic tunnel junctions with spin-transfer torque (STT) shows promise for unconventional computing, whereas its rigorous representation, based on the Neel-Arrhenius law, has been controversial. In particular, the exponents for thermally-activated switching rate therein, have been inaccessible with conventional thermally-stable nanomagnets with decade-long retention time. Here we approach the Neel-Arrhenius law with STT utilising superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determine the exponents through several independent measurements including homodyne-detected ferromagnetic resonance, nanosecond STT switching, and random telegraph noise. Furthermore, we show that the results are comprehensively described by a concept of local bifurcation observed in various physical systems. The findings demonstrate the capability of superparamagnetic tunnel junction as a useful tester for statistical physics as well as sophisticated engineering of probabilistic computing hardware with a rigorous mathematical foundation.

Journal Articles

Large antisymmetric interlayer exchange coupling enabling perpendicular magnetization switching by an in-plane magnetic field

Masuda, Hiroto*; Seki, Takeshi*; Yamane, Yuta*; Modak, R.*; Uchida, Kenichi*; Ieda, Junichi; Lau, Y.-C.*; Fukami, Shunsuke*; Takanashi, Koki

Physical Review Applied (Internet), 17(5), p.054036_1 - 054036_9, 2022/05

 Times Cited Count:1 Percentile:0(Physics, Applied)

The antisymmetric interlayer exchange coupling (AIEC) was recently discovered, playing pivotal roles in magnetization switching of a synthetic antiferromagnet (SAF) through inducing magnetization canting. Large AIEC is reported for perpendicularly magnetized Pt/Co/Ir/Co/Pt with wedge-shaped layers. The effective field of the AIEC is related with symmetric interlayer exchange coupling, providing guides to enhance the AIEC. We develop an extended Stoner-Wohlfarth model for a SAF, revealing key factors in its magnetization switching. Combining the theoretical knowledge and the experimental results, perpendicular magnetization switching is achieved solely by an in-plane magnetic field.

Journal Articles

Observation of domain structure in non-collinear antiferromagnetic Mn$$_3$$Sn thin films by magneto-optical Kerr effect

Uchimura, Tomohiro*; Yoon, J.-Y.*; Sato, Yuma*; Takeuchi, Yutaro*; Kanai, Shun*; Takechi, Ryota*; Kishi, Keisuke*; Yamane, Yuta*; DuttaGupta, S.*; Ieda, Junichi; et al.

Applied Physics Letters, 120(17), p.172405_1 - 172405_5, 2022/04

 Times Cited Count:3 Percentile:87.45(Physics, Applied)

Journal Articles

Theory of Emergent Inductance with Spin-Orbit Coupling Effects

Yamane, Yuta*; Fukami, Shunsuke*; Ieda, Junichi

Physical Review Letters, 128(14), p.147201_1 - 147201_6, 2022/04

 Times Cited Count:1 Percentile:0(Physics, Multidisciplinary)

We extend the theory of emergent inductance, which has recently been discovered in spiral magnets, to arbitrary magnetic textures by taking into account spin-orbit couplings arising in the absence of spatial inversion symmetry. We propose a new concept of spin-orbit emergent inductance, which can be formulated as originating from a dynamical Aharonov-Casher phase of an electron in ferromagnets. The spin-orbit emergent inductance universally arises in the coexistence of magnetism and the spin-orbit couplings, even with spatially uniform magnetization, allowing its stable operation in wide ranges of temperature and frequency. Revisiting the widely studied systems involving ferromagnets with spatial inversion asymmetry, with the new perspective offered by our work, will lead to opening a new paradigm in the study of spin-orbit physics and the spintronics-based power management in ultrawideband frequency range.

Journal Articles

Chiral-spin rotation of non-collinear antiferromagnet by spin-orbit torque

Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Ito, Ryuichi*; Jinnai, Butsurin*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*

Nature Materials, 20(10), p.1364 - 1370, 2021/10

 Times Cited Count:44 Percentile:98.8(Chemistry, Physical)

Journal Articles

Correlation of anomalous Hall effect with structural parameters and magnetic ordering in Mn$$_{3+x}$$Sn$$_{1-x}$$ thin films

Yoon, J.-Y.*; Takeuchi, Yutaro*; DuttaGupta, S.*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*

AIP Advances (Internet), 11(6), p.065318_1 - 065318_6, 2021/06

 Times Cited Count:8 Percentile:81.19(Nanoscience & Nanotechnology)

Journal Articles

Thermal stability of a magnetic domain wall in nanowires

Fukami, Shunsuke*; Ieda, Junichi; Ohno, Hideo*

Physical Review B, 91(23), p.235401_1 - 235401_7, 2015/06

 Times Cited Count:20 Percentile:66.72(Materials Science, Multidisciplinary)

We study thermal stability of a magnetic domain wall pinned in nanowires made of Co/Ni multilayers, and analyze the effective volume that governs the thermal stability. We find that, above a critical wire width, the domain wall depinning is initiated by a subvolume excitation and that the critical width is dependent on the wire thickness. The obtained findings are supported by the distribution of critical current density for domain wall depinning and are qualitatively described by considering the balance between the Zeeman energy and domain wall elastic energy.

7 (Records 1-7 displayed on this page)
  • 1