Publishing type：Research paper (scientific journal)   Publisher：American Physical Society (APS)  

DOI： 10.1103/PhysRevApplied.21.014051

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Scopus

Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevApplied.21.014051/fulltext

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Stable, reproducible, scalable, addressable, and controllable hybrid superconductor–semiconductor (S–Sm) junctions and switches are key circuit elements and building blocks of gate‐based quantum processors. The electrostatic field effect produced by the split gate voltages facilitates the realization of nano‐switches that can control the conductance or current in the hybrid S–Sm circuits based on 2D semiconducting electron systems. Here, a novel realization of large‐scale scalable, and gate voltage controllable hybrid field effect quantum chips is experimentally demonstrated. Each chip contains arrays of split gate field effect hybrid junctions, that work as conductance switches, and are made from In_0.75Ga_0.25As quantum wells integrated with Nb superconducting electronic circuits. Each hybrid junction in the chip can be controlled and addressed through its corresponding source–drain and two global split gate contact pads that allow switching between their (super)conducting and insulating states. A total of 18 quantum chips are fabricated with 144 field effect hybrid Nb‐ In_0.75Ga_0.25As 2DEG‐Nb quantum wires and the electrical response, switching voltage (on/off) statistics, quantum yield, and reproducibility of several devices at cryogenic temperatures are investigated. The proposed integrated quantum device architecture allows control of individual junctions in a large array on a chip useful for emerging cryogenic quantum technologies.

DOI： 10.1002/aelm.202300453

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Proximity-induced long-range spin-triplet supercurrents, important for the field of superconducting spintronics, are generated in superconducting/ferromagnetic heterostructures when interfacial magnetic inhomogeneities responsible for spin mixing and spin flip scattering are present. The multilayer stack Nb/Cr/Fe/Cr/Nb has been shown to support such currents when fabricated into Josephson junction devices. However, creating pure spin currents controllably in superconductors outside of the Josephson junction architecture is a bottleneck to progress. Recently, ferromagnetic resonance was proposed as a possible direction, the signature of pure supercurrent creation being an enhancement of the Gilbert damping below the superconducting critical temperature, but the necessary conditions are still poorly established. Here, we demonstrate that pumping pure spin currents into a superconductor in the presence of an external magnetic field is only possible when conditions supporting proximity-induced spin-triplet effects are satisfied. Our study is an important step forward for pure spin supercurrent creation, considerably advancing the field of superconducting spintronics.

DOI： 10.1038/s42005-023-01384-w

Other Link： https://www.nature.com/articles/s42005-023-01384-w

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

We report the magnetic and spin frustration properties of Ag-based honeycomb layered tellurates with magnetic honeycomb slabs separated by Ag bilayers.

DOI： 10.1039/d3tc01915b

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Scopus

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physical Society (APS)  

DOI： 10.1103/PhysRevApplied.19.064077

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Scopus

Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevApplied.19.064077/fulltext

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AIP Publishing  

In recent years, antiferromagnetic materials have been attracting increasing interest for their stability in high magnetic fields and ultrafast magnetization dynamics. Since the energy scale of an interlayer exchange coupling (IEC) in a synthetic antiferromagnet (SAF) consisting of ferromagnetic/nonmagnetic/ferromagnetic multilayers is relatively smaller than that of an exchange coupling in antiferromagnetic materials, magnetic ordering of a SAF can be potentially controlled by an electric field, which is promising for energy-saving spintronic memory devices. However, an electric field-induced magnetoelastic response of SAFs on ferroelectric materials has not been sufficiently understood due to the presence of IEC that complicates magnetization dynamics. In this study, we prepare Co/Ru/Co SAFs with various amplitude of IEC on ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 substrates and systematically investigate their electric field-induced magnetoelastic response. We demonstrate that the magnetoelastic response disappears at the boundary where a switching between the antiferromagnetic and ferromagnetic IEC coupling occurs. The result provides insight into the coupling of the magnetoelastic effect and IEC and is useful in designing spintronic memory devices based on SAFs.

DOI： 10.1063/5.0151832

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AIP Publishing  

In La1−xSrxMnO3 (LSMO)/BaTiO3 (BTO) heterostructures with a multiferroic interface, an artificial modulation of the magnetic structure is observed. The saturation magnetization of La1−xSrxMnO3 changes discontinuously due to in-plane distortions caused by a structural phase transition of a BaTiO3 substrate. Polarity reversal of the external electric field also causes a reversible switching in the magnetization. The magnitude of both magnetic modulations, due to the magnetoelastic and electric field effects, is concomitantly enhanced at a critical composition xc∼0.55, locating at a border of the magnetic phase transition. The polarity-dependent change in magnetization is possibly attributed to a change in the concentration of oxygen ions at the LSMO/BTO interface, indicating that the exchange interaction is reciprocally driven from being ferromagnetic to antiferromagnetic by the electric field polarity.

DOI： 10.1063/5.0150917

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Scopus

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/intermagshortpapers58606.2023.10228509

Scopus

Publisher：2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings  

Piezoelectric LiNbO3 has been widely utilized to generate and detect spin waves in surface acoustic wave devices. Here we demonstrate an epitaxial Co-based Heusler alloy on a LiNbO3 128° Y-cut (LN-128Y) substrate by molecular beam epitaxy. Although there is no matching between the lattice length and symmetry, the insertion of a bcc metal buffer layer enables to grow L21 - ordered epitaxial Co2FeSi films on the LN-128Y substrate. The epitaxial Co2FeSi/LN- 128Y multiferroic heterostructures show a high saturation magnetization of ~1235 eμcc and a low damping constant of ~6 × 10-3. This study will open a way for an efficient electric-field control of the spin waves in surface acoustic wave devices.

DOI： 10.1109/INTERMAGShortPapers58606.2023.10228793

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaelm.2c00967

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr₂RuO₄, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr₂RuO₄ is still ongoing, a deeper understanding of the Sr₂RuO₄ normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr₂RuO₄ in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr₂RuO₄ surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.

DOI： 10.1038/s41467-021-26020-5

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Scopus

PubMed

Other Link： https://www.nature.com/articles/s41467-021-26020-5

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.nanolett.1c01607

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Physical Society of Japan  

DOI： 10.7566/jpsj.90.024702

Publishing type：Research paper (scientific journal)   Publisher：American Physical Society (APS)  

DOI： 10.1103/physrevmaterials.5.014413

Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevMaterials.5.014413/fulltext

Event date： 2023.3

Event date： 2023.3

Event date： 2023.2

Event date： 2022.11

Presentation type：Oral presentation (invited, special)  

Event date： 2022.11

Presentation type：Oral presentation (invited, special)  

Event date： 2021.10

Event date： 2021.9