Fabrication of fully epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions

Fully epitaxial magnetic tunnel junctions (MTJs) were fabricated with full-Heusler alloy Co2MnSi thin films as both lower and upper electrodes and with a MgO tunnel barrier. The fabricated MTJs showed clear exchange-biased tunnel magnetoresistance (TMR) characteristics with high TMR ratios of 179% at room temperature (RT) and 683% at 4.2 K. In addition, the TMR ratio exhibited oscillations as a function of the MgO tunnel barrier thickness (t(MgO)) at RT, having a period of 0.28 nm, for t(MgO) ranging from 1.8 to 3.0 nm.