Abstract
A spin valve is a microelectronic device in which high- and low-resistance states are realized by using both the charge and spin of carriers. Spin-valve structures used in modern hard-drive read heads and magnetic random access memoriescomprise two ferromagnetic electrodes whose relative magnetization orientations can be switched between parallel and antiparallel configurations, yielding the desired giant or tunnelling magnetoresistance effect1. Here we demonstrate more than 100% spin-valve-like signal in a NiFe/IrMn/MgO/Pt stack with an antiferromagnet on one side and a non-magnetic metal on the other side of the tunnel barrier. Ferromagneticmoments in NiFe are reversed by external fields of approximately50 mT or less, and the exchange-spring effect2 of NiFe on IrMn induces rotation of antiferromagnetic moments in IrMn, which is detected by the measured tunnelling anisotropic magnetoresistance3. Our work demonstrates a spintronic element whose transport characteristics are governed by an antiferromagnet. It demonstrates that sensitivity to low magnetic fields can be combined with large, spin-orbit-coupling-induced magnetotransport anisotropy using a single magnetic electrode. The antiferromagnetic tunnelling anisotropic magnetoresistance provides a means to study magnetic characteristics of antiferromagnetic films by an electronic-transport measurement.
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Acknowledgements
We acknowledge support from EU Grant FP7-214499 NAMASTE, FP7-215368 SemiSpinNet, ERC Advanced Grant 268066—0MSPIN and Czech Republic Grants from AV0Z10100521, KAN400100652, LC510 and Preamium Academiae.
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Device fabrications, Y.K., M.Y., H.Y., A.N., J.H., H.T., B.G.P., J.W.; experiments and data analysis, B.G.P., J.W., X.M., A.B.S., V.H., T.J.; writing, T.J., J.W.; project planning, J.W.,T.J., B.G.P., X.M., A.B.S., J.H., H.T.
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Park, B., Wunderlich, J., Martí, X. et al. A spin-valve-like magnetoresistance of an antiferromagnet-based tunnel junction. Nature Mater 10, 347–351 (2011). https://doi.org/10.1038/nmat2983
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DOI: https://doi.org/10.1038/nmat2983
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