Optimization of tunneling magnetoresistance in perpendicular magnetic tunnel junctions with CO\Pd reference layers

We report on the optimization of Co\Pd-multilayer-based reference layers in magnetic tunnel junctions with perpendicular magnetic anisotropy. By inserting a thin Ta-spacer layer between the CoFeB interfacial layer and Co\Pd multilayer, a high tunneling magnetoresistance up to 98.5% can be achieved. Electron energy loss spectroscopy and synchrotron X-ray diffraction studies show that the high magnetoresistance is related primarily to the suppression of Pd diffusion and secondarily to improved CoFeB texture during annealing. © 2010-2012 IEEE.