The magnetostriction (lambda(s)) and tunneling magnetoresistance (TMR) of two Co/AlO(x)/Co/IrMn MTJ systems that were deposited on Si(100) and glass substrate were examined at RT and field-annealing with various thicknesses of AlO(x). One structure was a Si(100)/Ta/Co/AlO(x)/Co/IrMn/Ta system, and the other was a glass/Co/AlO(x)/Co/IrMn system. The experimental results reveal that, in the Si(100)/Ta/Co/AlO(x)/Co/IrMn/Ta system, the ratio of TMR is maximal under the field-annealing condition, and is optimal at an AlO(x) thickness of 26 angstrom as well as in the RT condition. EDS analysis demonstrates that, these results are related to the distribution of Co and O atoms, because the oxidation of AlO(x) is most extensive at a thickness of 26 angstrom. In the glass/Co/AlO(x)/Co/IrMn system, lambda(s) does not significantly vary under the RT condition; however, lambda(s) is maximized (-20 ppm) by field-annealing at an AlO(x) thickness of 17 angstrom. The abundance of Co and O in the system dominates the behavior of lambda(s), according to EDS analysis. Finally, the minimum value of lambda(s) and the maximum ratio of TMR are -8 ppm and 60%, respectively, at an AlO(x) thickness of 26 angstrom under the field-annealing condition. (c) 2009 Elsevier B.V. All rights reserved.
