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A method for detecting dc spin current propagation through an epitaxial antiferromagnetic (AFM) NiO layer is presented. Spin current is generated by spin pumping from an adjoining ferromagnetic (FM) layer and detected in a non-magnetic metallic layer by the inverse spin Hall effect. Comparison is made with a YIG/Pt bilayer, where only the Pt layer is electrically conducting, but for which spin Hall magnetoresistance makes an additional contribution to the measured signal. The signal obtained from the multilayered stack containing the AFM NiO layer is found to contain additional contributions due to anisotropic magnetoresistance. By exciting the sample with out-of-plane rf magnetic field and making measurements with a static field applied at different orientations within the plane of the sample, a signal associated with the dc spin current may be identified. [ABSTRACT FROM AUTHOR]

Conventional electronic article surveillance (EAS) tags are ineffective on metallic packaging. The component of the RF magnetic field perpendicular to the surface of the packaging induces eddy currents that suppress the magnetic flux, linking the inductive element of the tag. In this article, an inductive quarter-wavelength planar cavity, formed by wrapping aluminum foil around a ferrite core, was extended by wrapping additional capacitive layers of foil/dielectric around the ferrite-filled central region. This so-called wrapped tag exhibits the frequency, $Q$ -factor, and read distance characteristics of existing EAS tags, but is instead driven by the RF magnetic fields parallel to the surface of the metallic packaging. In this article, we compare the observed frequency response of the wrapped tag with a simple LC resonator model that considers the tag’s geometrical features, and use the model to describe how the design and construction of the tag can be optimized. Finite-element method (FEM) modeling is used to reveal how the current flows in the wrapped foil of the tag. Prototype tags show good reproducibility, demonstrating the potential of the design as a solution to the problem of tagging metallic packaging in the EAS industry. [ABSTRACT FROM AUTHOR]