A puzzling insensitivity of magnon spin diffusion to the presence of 180-degree domain walls

Ruofan Li; Lauren J Riddiford; Yahong Chai; Minyi Dai; Hai Zhong; Bo Li; Peng Li; Di Yi; Yuejie Zhang; David A Broadway; Adrien E E Dubois; Patrick Maletinsky; Jiamian Hu; Yuri Suzuki; Daniel C Ralph; Tianxiang Nan

doi:10.1038/s41467-023-38095-3

A puzzling insensitivity of magnon spin diffusion to the presence of 180-degree domain walls

Nat Commun. 2023 Apr 26;14(1):2393. doi: 10.1038/s41467-023-38095-3.

Authors

Ruofan Li¹, Lauren J Riddiford², Yahong Chai³, Minyi Dai⁴, Hai Zhong⁵, Bo Li⁶, Peng Li², Di Yi^{2

7}, Yuejie Zhang³, David A Broadway⁸, Adrien E E Dubois^{5

8}, Patrick Maletinsky^{5

8}, Jiamian Hu⁴, Yuri Suzuki^{2

9}, Daniel C Ralph^{10

11}, Tianxiang Nan^{12

13}

Affiliations

¹ Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY, 14853, USA.
² Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
³ School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, 100084, Beijing, China.
⁴ Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
⁵ Qnami AG, CH-4132, Muttenz, Switzerland.
⁶ Institute for Advanced Study, Tsinghua University, 100084, Beijing, China.
⁷ State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
⁸ Department of Physics, University of Basel, CH-4056, Basel, Switzerland.
⁹ Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
¹⁰ Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY, 14853, USA. dcr14@cornell.edu.
¹¹ Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA. dcr14@cornell.edu.
¹² Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY, 14853, USA. nantianxiang@mail.tsinghua.edu.cn.
¹³ School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, 100084, Beijing, China. nantianxiang@mail.tsinghua.edu.cn.

Abstract

We present room-temperature measurements of magnon spin diffusion in epitaxial ferrimagnetic insulator MgAl_0.5Fe_1.5O₄ (MAFO) thin films near zero applied magnetic field where the sample forms a multi-domain state. Due to a weak uniaxial magnetic anisotropy, the domains are separated primarily by 180° domain walls. We find, surprisingly, that the presence of the domain walls has very little effect on the spin diffusion - nonlocal spin transport signals in the multi-domain state retain at least 95% of the maximum signal strength measured for the spatially-uniform magnetic state, over distances at least five times the typical domain size. This result is in conflict with simple models of interactions between magnons and static domain walls, which predict that the spin polarization carried by the magnons reverses upon passage through a 180° domain wall.

Abstract

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