title: Enhancement of Thermally Injected Spin Current through an Antiferromagnetic Insulator.
abstract: We report a large enhancement of thermally injected spin current in normal metal (NM)/antiferromagnet (AF)/yttrium iron garnet (YIG), where a thin AF insulating layer of NiO or CoO can enhance the spin current from YIG to a NM by up to a factor of 10. The spin current enhancement in NM/AF/YIG, with a pronounced maximum near the Néel temperature of the thin AF layer, has been found to scale linearly with the spin-mixing conductance at the NM/YIG interface for NM=3d, 4d, and 5d metals. Calculations of spin current enhancement and spin mixing conductance are qualitatively consistent with the experimental results.
authors.affiliation: Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Lin
authors.affiliation: Department of Physics, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Physics, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Shufeng
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Chien