Effect of Annealing and Barrier Thickness on MgO-Based Co/Pt and Co/Pd Multilayered Perpendicular Magnetic Tunnel Junctions

Abstract

In this study, the effects of annealing conditions on the magnetic characteristics of multilayered perpendicular magnetic tunnel junctions (pMTJ) of the structures SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /Pt/(Co/Pd) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> /MgO/(Co/Pt) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> /Pt with various MgO barrier thicknesses were explored. We found that both the fixed and free layers exhibit coercivity growth with increasing annealing temperature. Insertion of a 0.4 nm Mg layer under the MgO barrier layer increases the corecivities further. Magnetoresistance measured by the current-in-plane tunneling (CIPT) method reveals that the insertion of Mg layers on both side of the MgO layer can increase the MR ratio by up to 32%.