An insulating doped antiferromagnet with low magnetic symmetry as a room temperature spin conduit

Abstract

We report room temperature long-distance spin transport of magnons in antiferromagnetic thin film hematite doped with Zn. The additional dopants significantly alter the magnetic anisotropies, resulting in a complex equilibrium spin structure that is capable of efficiently transporting spin angular momentum at room temperature without the need for a well-defined, pure easy-axis or easy-plane anisotropy. We find intrinsic magnon spin-diffusion lengths of up to 1.5 μm, and magnetic domain governed decay lengths of 175 nm for the low frequency magnons, through electrical transport measurements demonstrating that the introduction of non-magnetic dopants does not strongly reduce the transport length scale showing that the magnetic damping of hematite is not significantly increased. We observe a complex field dependence of the non-local signal independent of the magnetic state visible in the local magnetoresistance and direct magnetic imaging of the antiferromagnetic domain structure. We explain our results in terms of a varying and applied-field-dependent ellipticity of the magnon modes reaching the detector electrode allowing us to tune the spin transport.

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• Spin pumping and shot noise in ferrimagnets: bridging ferro- and antiferromagnets
• Magnetic states at the surface of alpha-Fe2O3 thin films doped with Ti, Zn or Sn
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• Anisotropic long-range spin transport in canted antiferromagnetic orthoferrite YFeO${}_3$
• Observation of nonreciprocal magnon Hanle effect
• Exceptional sign changes of the non-local spin Seebeck effect in antiferromagnetic hematite
• All-electrical Magnon Transport Experiments in Magnetically Ordered Insulators
• Revealing the Altermagnetism in Hematite via XMCD Imaging and Anomalous Hall Electrical Transport
• Micromagnetic study of spin transport in easy-plane antiferromagnetic insulators
• Magnon Transport in the Presence of Antisymmetric Exchange in a Weak Antiferromagnet
• Influence of low-energy magnons on magnon Hanle experiments in easy-plane antiferromagnets
• Squeezing and quantum control of antiferromagnetic magnon pseudospin
• Thickness-dependent magnon spin transport in antiferromagnetic insulators: Crossover from quasi-three-dimensional to quasi-two-dimensional regimes
• Nonreciprocal Magnon Hanle Effect in Antiferromagnetic $\alpha$-Fe${}_2$O${}_3$