The tunnel magnetoresistance (TMR) effect has been investigated for magnetic tunnel junctions with epitaxial Co2FeAl0.5Si 0.5 Heusler electrodes with 52 and L21 structures on a Cr-bufferd MgO substrate. The epitaxially grown Co2FeAl 0.5Si0.5 has B2 structure when annealed below 400 °C, and has L21 structure for annealing above 450 °C. The TMR ratio of 76% at room temperature and 106% at 5 K were obtained for a MgO(001)/Cr/B2-type Co2FeAl0.5Si0.5/Al oxide/ Co75Fe25/IrMn/Ta. The TMR ratio is larger than that of magnetic tunnel junction with an L21-type electrode, which may be due to the smoother surface of the B2 structure and disordered L21 structure due to the Cr atom interdiffusion.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)