1. Birefringence-like spin transport via linearly polarized antiferromagnetic magnons
- Author
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Jiahao Han, Ran Cheng, Zhen Bi, Liang Fu, Luqiao Liu, Junxiang Xiang, Pengxiang Zhang, Yabin Fan, Taqiyyah S. Safi, and Joseph Finley
- Subjects
Physics ,Angular momentum ,Condensed matter physics ,Spins ,Spintronics ,Magnon ,Demagnetizing field ,Biomedical Engineering ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Magnetic field ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology ,Spin-½ - Abstract
Antiferromagnets (AFMs) possess great potential in spintronics because of their immunity to external magnetic disturbance, the absence of a stray field or the resonance in the terahertz range1,2. The coupling of insulating AFMs to spin–orbit materials3–7 enables spin transport via AFM magnons. In particular, spin transmission over several micrometres occurs in some AFMs with easy-axis anisotropy8,9. Easy-plane AFMs with two orthogonal, linearly polarized magnon eigenmodes own unique advantages for low-energy control of ultrafast magnetic dynamics2. However, it is commonly conceived that these magnon modes are less likely to transmit spins because of their vanishing angular momentum9–11. Here we report experimental evidence that an easy-plane insulating AFM, an α-Fe2O3 thin film, can efficiently transmit spins over micrometre distances. The spin decay length shows an unconventional temperature dependence that cannot be captured considering solely thermal magnon scatterings. We interpret our observations in terms of an interference of two linearly polarized, propagating magnons in analogy to the birefringence effect in optics. Furthermore, our devices can realize a bi-stable spin-current switch with a 100% on/off ratio under zero remnant magnetic field. These findings provide additional tools for non-volatile, low-field control of spin transport in AFM systems. Easy-plane antiferromagnet materials promise low-energy control of ultrafast magnetic dynamics in future spintronics applications, but host magnons with vanishing angular momentum, which makes spin transport via magnons unlikely. Through interference of two linearly polarized propagating magnons, spin transport over micrometre distances is yet possible.
- Published
- 2020