Spin-dependent tunneling in self-assembled cobalt-nanocrystal superlattices.
Self-assembled devices composed of periodic arrays of 10-nanometer-diameter cobalt nanocrystals display spin-dependent electron transport. Current-voltage characteristics are well described by single-electron tunneling in a uniform array. At temperatures below 20 kelvin, device magnetoresistance ratios are on the order of 10%, approaching the maximum predicted for ensembles of cobalt islands with randomly oriented preferred magnetic axes. Low-energy spin-flip scattering suppresses magnetoresistance with increasing temperature and bias-voltage.
Black
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IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598, USA. ctblack@us.ibm.com
Murray
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Sandstrom
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Sun
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