CoFeB Thickness Dependence of Thermal Stability Factor in CoFeB/MgO Perpendicular Magnetic Tunnel Junctions

摘要

Thermal stability factor (delta) of recording layer was studied inperpendicular anisotropy CoFeB/MgO magnetic tunnel junctions (p-MTJs) withvarious CoFeB recording layer thicknesses and junction sizes. In all series ofp-MTJs with different thicknesses, delta is virtually independent of thejunction sizes of 48-81 nm in diameter. The values of delta increase linearlywith increasing the recording layer thickness. The slope of the linear fit isexplained well by a model based on nucleation type magnetization reversal.