We fabricated perpendicularly magnetized magnetic tunnel junctions (p-MTJs) with an ultrathin Co 2FeAl (CFA) full-Heusler alloy electrode having large interface magnetic anisotropy of CFA/MgO. An out-of-plane tunnel magnetoresistance (TMR) ratio of 53% at room temperature was observed in CFA/MgO/Co 20Fe 60B 20 p-MTJs. By inserting a 0.1-nm-thick Fe (Co 50Fe 50) layer between the MgO and Co 20Fe 60B 20 layers, The TMR ratio was significantly enhanced to 91% (82%) due to the improved interface. The bias voltage dependence of differential conductance did not clearly show coherent tunneling characteristics for ultrathin CFA-MTJs, suggesting that a higher TMR ratio may be achieved by improving the B2 ordering of CFA and/or interface structure.
ASJC Scopus subject areas
- Physics and Astronomy(all)