AlHf合金バリアを用いたTMR積層膜の諸特性

概要

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We investigated the tunnel magnetoresistance(TMR) and bias voltage dependence of the TMR with oxidized Al-Hf Alloy at the range of Hf content (C_<Hf>) from 0 at.% to 70 at.%. The TMR ratio was greatly increased from 9.6% to 21.4% when the C_<Hf> increased from 0 at.% to 17 at.%, and the critical AlHf thickness that appeared TMR raito was thinner with C_<Hf> increased. These results are explained by the consideration that a uniformity of the oxidation in the AlHf layer composed with an amorphous or a nano-crystallized state was better than that in the Allayer composed with the large grain-boundaries such as fcc-Al. The bias voltage dependence of the TMR with oxidized Al-Hf Alloy at C_<Hf> of 17 at.% also improved and the yield that tunnel junction had high breakdown voltage was better than that with Al-oxide barrier although barrier thickness became thin in order to decrease RA. These results indicate that the defects like pinholes in oxidized Al-Hf Alloy barrier decreased because the crystal structure of Al was changed into amorphous from fcc(111) by Hf.
社団法人日本磁気学会の論文
2006-01-01