Improved tunnel magnetoresistance characteristics of magnetic tunnel junctions with a Heusler alloy thin film of Co2MnGe and a MgO tunnel barrier

We fabricated magnetic tunnel junctions (MTJs) with a Co-based full-Heusler alloy thin film of Co2MnGe (CMG) and a MgO tunnel barrier. The microfabricated MTJs with a Co-rich CMG film showed relatively high tunnel magnetoresistance ratios of 83% at room temperature and 185% at 4.2 K. These values are much higher than those previously obtained for CMG/MgO MTJs with a Co-deficient CMG film. (c) 2007 American Institute of Physics.