Oral Session C2 (Thursday, February 15)
Chair: Cheng Song, Tsinghua University

Contributed Oral
10: 55 - 11 : 15

Anisotropic spin polarized current and magnetoresistancein an antiferromagnetic tunnel junction
Xianzhe Chen1, 2, Tomoya Higo1, 2, Katsuhiro Tanaka2, 3, Takuya Nomoto3, Hanshen
Tsai2, Hiroshi Idzuchi2, Masanobu Shiga1, Shoya Sakamoto1, Hidetoshi Kosaki1,Takumi Matsuo2, Daisuke Nishio-Hamane1, Ryotaro Arita3, 4, Shinji Miwa1, 5, andSatoru Nakatsuji1, 2, 5, 6
1. The Institute for Solid State Physics, The University of Tokyo, Japan
2. Department of Physics, The University of Tokyo, Japan
3. Research Center for Advanced Science and Technology, The University of Tokyo, Japan
4. Center for Emergent Matter Science (CEMS), RIKEN, Japan
5. Trans-scale Quantum Science Institute, The University of Tokyo, Japan
6. Institute for Quantum Matter, Johns Hopkins University, USA
Tunnel magnetoresistance (TMR) and spin-transfer torque (STT), due to longitudinal spin-polarized current,
provide the read and write protocols for the two-terminal magnetoresistive devices. In addition to thewell-established ferromagnetic spintronics, antiferromagnets have attracted considerable interest as next-generation
active elements for further improvements in operating speed and integration density. Therefore, it is important todevelop both TMR and STT using all-antiferromagnetic tunnel junctions. In principle, TMR eﬀect inall-antiferromagnetic tunnel junction is feasible in terms of momentum-dependent spin polarization [1]. However, it
is diﬃcult to prepare such time-reversal odd and controllable spin state in collinear antiferromagnet. Therefore, noreports have been published on the TMR eﬀect using an all-antiferromagnetic tunnel junction. In addition, theobservation and manipulation of the longitudinal spin-polarized current is necessary as a basis for the design of thememory device based solely on antiferromagnets, but, again, it has never been carried out for antiferromagnets. In
this talk, we show that high-quality epitaxial thin films of the Weyl antiferromagnet Mn3Sn [2] could be prepared bymolecular beam epitaxy [3]. We clarify the existence of anisotropic, longitudinal spin-polarized current [4] using Fe/MgO/Mn3Sn-MTJ and achieve TMR in an all-antiferromagnetic tunnel junction comprising Mn3Sn/MgO/Mn3Sn [5].
This work was supported by JST-MIRAI Program, JST-CREST, JSPS-KAKENHI , Spin-RNJ, andMEXT-XNICS.

References[1] D.-F. Shao et al., Nat. Commun. 12, 7061 (2021).
[2] S. Nakatsuji et al., Nature 527, 212 (2015).
[3] T. Higo et al., Nature 607, 404 (2022).
[4] J. Železný et al., Phys. Rev. Lett. 119, 187204 (2017).
[5] X. Chen et al., Nature 613, 490 (2023).

Oral Session C2 (Thursday, February 15)
Chair: Cheng Song, Tsinghua University

Contributed Oral
11: 15 - 11 : 35

First-principles study on tunnel magnetoresistance eﬀect
with antiferromagnets
Katsuhiro Tanaka1, Takuya Nomoto2, and Ryotaro Arita2, 3
1. Department of Physics, The University of Tokyo, Japan
2. Research Center for Advanced Science and Technology, The University of Tokyo, Japan
3. Center for Emergent Matter Science (CEMS), RIKEN, Japan
Recent studies have shown that the antiferromagnets macroscopically breaking the time-reversal symmetry canexhibit a finite tunnel magnetoresistance (TMR) eﬀect [1–4]. Particularly, we have focused on Mn3Sn, anoncollinear antiferromagnet whose time-reversal breaking magnetic structure can be regarded as the ferroicorder of the cluster magnetic octupole moments [5]. We have shown that Mn3Sn can have a finite TMR eﬀect
from first principles, and we have actually observed the TMR eﬀect in experiments [3].
To understand the TMR eﬀect with antiferromagnets more closely, we have dealt with simple lattice models withcollinear magnets. We have found that the local density of states inside the tunneling barrier can be an easy probe
to discuss the TMR eﬀect qualitatively [6]. As its application to first-principles calculations, we will discuss theTMR eﬀect with Cr doped RuO2; the rutile-type RuO2, an antiferromagnet, shows intriguing phenomena thanks
to its magnetic structure [1, 7], and its magnetism is reinforced by doping Cr into RuO2 [8].

References[1] D.-F. Shao et al., Nat. Commun. 12, 7061 (2021).
[2] J. Dong et al., Phys. Rev. Lett. 128, 197201 (2022).
[3] X. Chen, T. Higo, K. Tanaka et al., Nature 613, 490 (2023).
[4] P. Qin et al., Nature 613, 485 (2023).
[5] M.-T. Suzuki, T. Koretsune, M. Ochi, and R. Arita, Phys. Rev. B 95, 094406 (2017).
[6] K. Tanaka, T. Nomoto, and R. Arita, Phys. Rev. B 107, 214442 (2023).
[7] T. Berlijn et al., Phys. Rev. Lett. 118, 077201 (2017); L. Šmejkal et al., Sci. Adv. 6, eaaz8809 (2020); Z. Feng et al., Nat.
Electro. 5, 735 (2022).
[8] M. Wang, K. Tanaka et al., Nat. Commun. 14, 8240 (2023).

Oral Session C2 (Thursday, February 15)
Chair: Cheng Song, Tsinghua University

Contributed Oral
11: 35 - 11 : 55Magnetic tunnel junction-based readout for spin Hallnano-oscillators
Akash Kumar1, 2, Takaaki Dohi2, Mohammad Zahedinejad1, Roman Khymyn1
Shun Kanai2, Shunsuke Fukami2 and Johan Åkerman1, 2
1. Applied Spintronics Group, Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden
2. Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku
University, Sendai, Japan
Since their demonstration, nano-constriction spin Hall nano-oscillators (NC-SHNOs) have gained substantial
attention for their easy nano-fabrication, coherent signal, and large frequency-tunability[1]. Their superiority inmutual synchronization exhibited in both onedimensional chains [2,3] and two-dimensional arrays [4] positions
these oscillators as building-blocks in diverse unconventional computing schemes, including
reservoir/neuromorphic computing [4,5], and Ising machines [6]. Despite their potential, the low anisotropic
magneto-resistance (AMR) of ferromagnetic materials limits their practical applications. Various eﬀorts have been
undertaken to enhance the output power of NC-SHNOs, such as incorporating large easy-plane anisotropy [7]and exploiting giant magneto-resistance [8].
This study introduces a groundbreaking approach by integrating a magnetic tunnel junction (MTJ)-based read-outfor SHNO devices, resulting in MTJ-SHNOs with superior spectral characteristics. These devices exhibit large
output power due to significant tunnelling magnetoresistance (>70%) while maintaining a low linewidth andpreserving original magnetodynamical mode of SHNOs. Experiments demonstrate a remarkable 104 increment in
output power (>5 nWs from 0.5 pW) without additional input. Moreover, the MTJ pillars provide a means forindividual control of SHNOs through an additional current path and enable local probing/control within large
chains or arrays. These advancements not only overcome NC-SHNOs’ output power limitations but also enables
additional control, facilitating their eﬀective integration into practical applications.
References[1] V. E. Demidov et al., Appl. Phys. Lett. 105, 172410 (2014).
[2] A. A. Awad et al., Nat. Phy. 13, 292 (2018).
[3] A. Kumar et al., Nano Lett. 23, 6720 (2023).
[4] M. Zahedinejad et al., Nat. Nano. 15, 47 (2020).
[5] M. Zahedinejad et al., Nat. Mat. 21, 81 (2022).
[6] A. Houshang et al., Phys. Rev. Appl. 17, 014003 (2022).
[7] E. Montoya et al., Comm. Phys. 6, 184 (2023).
[8] J-R. Chen et al., Comm. Phys. 3, 187 (2020).