Magnetic tunnel junctions using B2-ordered Co2MnAl Heusler alloy epitaxial electrode -: art. no. 022503

Magnetic tunnel junctions were fabricated with epitaxially grown Co2MnAl bottom electrodes combined with an Al-O tunnel barrier using a magnetron sputtering system. The epitaxial Co2MnAl electrode had very low surface roughness of 0.2 nm and a highly ordered B2 structure. Magnetic tunnel junctions (MTJs) with a stacking structure of epitaxial-Co2MnAl/Al-O/CoFe/IrMn exhibited large tunnel magnetoresistance (TMR) ratios of 65% at room temperature and 83% at 10 K. The TMR ratios were larger than those of a MTJ with a Co2MnAl polycrystalline electrode.