Anomalous magnetoresistance behavior of CoFe nano-oxide spin valves at low temperatures

摘要

We report magnetoresistance curves of CoFe nano-oxide specular spin valves ofMnIr/CoFe/nano-oxidized CoFe/CoFe/Cu/CoFe/nano-oxidized CoFe/Ta at differenttemperatures from 300 to 20 K. We extend the Stoner-Wolfarth model of a commonspin valve to a specular spin valve, introducing the separation of the pinnedlayer into two sublayers and their magnetic coupling across the nano-oxide. Westudy the effect of different coupling/exchange (between the antiferromagneticlayer and the bottom sublayer) field ratios on the magnetization andmagnetoresistance, corresponding with the experimentally observed anomalousbumps in low temperature magnetoresistance curves.