Antiferromagnetic materials can host spin-waves with polarizations ranging from circular to linear depending on their magnetic anisotropies. Until now, only easy-axis anisotropy antiferromagnets with circularly polarized spin-waves were reported to carry spin-information over long distances of micrometers. In this article, we report long-distance spin-transport in the easy-plane canted antiferromagnetic phase of hematite and at room temperature, where the linearly polarized magnons are not intuitively expected to carry spin. We demonstrate that the spin-transport signal decreases continuously through the easy-axis to easy-plane Morin transition, and persists in the easy-plane phase through current induced pairs of linearly polarized magnons with dephasing lengths in the micrometer range. We explain the long transport distance as a result of the low magnetic damping, which we measure to be ≤ 10-5 as in the best ferromagnets. All of this together demonstrates that long-distance transport can be achieved across a range of anisotropies and temperatures, up to room temperature, highlighting the promising potential of this insulating antiferromagnet for magnon-based devices.

Center for Quantum Spintronics Department of Physics Norwegian University of Science and Technology Trondheim Norway

Graduate School of Excellence Materials Science in Mainz Staudingerweg 9 55128 Mainz Germany

Institut für Physik Johannes Gutenberg Universität Mainz 55099 Mainz Germany

Institute of Physics ASCR v v i Cukrovarnicka 10 162 53 Praha Czech Republic

Laboratoire National des Champs Magnétiques Intenses CNRS UGA UPS INSA EMFL 38042 Grenoble France

Unité Mixte de Physique CNRS Thales Université Paris Saclay 91767 Palaiseau France

Univ Grenoble Alpes CNRS CEA Grenoble INP SPINTEC 38000 Grenoble France

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