Magnetic properties of MgO-[Co/Pt] multilayers with a CoFeB insertion layer

Magnetic properties of MgO-[Co/Pt] multilayers with a CoFeB insertion layer were investigated and the structure was adopted as a recording layer in magnetic tunnel junctions (MTJs) with perpendicular magnetic easy-axis to attain a high thermal stability. Perpendicular easy-axis was obtained with the Pt thickness range of 0.6-1.2 nm and the CoFeB thickness range of 0.6-1.5 nm. As-made MTJs employing the CoFeB-[Co/Pt] multilayer structure as a recording layer showed tunnel magnetoresistance of 40% on average. A high thermal stability factor over 200 was obtained in the MTJs with the size of 25 nm in diameter. (C) 2013 American Institute of Physics.