Magnetoresistance behavior of a magnetic tunnel junction with perpendicularly magnetized Co/Pd multilayers

We investigated perpendicularly magnetized magnetic tunnel junctions (pMTJs) using Co/Pd multilayers and the effects of multilayer structure on the magnetoresistance. We obtained a tunneling magneto-resistance (TMR) ratio of 12.6% in a pseudo-pMTJ with a 9-nm-thick Pd underlayer. The number of bilayers of Pd/Co affected the magnetic anisotropy and the junction resistance. The TMR increased with the Pd underlayer because the interface uniformity and interface structure of the tunnel barrier (AlOx) layer were improved. An exchange-biased pMTJ with IrMn had a small TMR because the antiferromagnetic layer increased the resistance of the pMTJ and reduced the spin polarization. (c) 2005 American Institute of Physics.