Electric-field control of CoFeB/IrMn exchange bias system

The electrically controlled spintronic devices based on magnetism at the interface is a key challenge today. We have studied the top sub./CoFeB/IrMn and bottom sub./IrMn/CoFeB pinned exchange bias systems as a function of electric field at room temperature deposited on the (011) - Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) piezoelectric substrate. It was found that the electric-field tuning of exchange bias was very small although both the structures show good regular magnetoelectric coupling. We propose an alternative way to control the exchange bias via electric field in the multilayered structure by inserting a metallic spacer layer between exchange bias bilayer and bottom free magnetic layer, i.e., PMN-PT/CoFeB/Cu/CoFeB/IrMn. We successfully tuned the exchange bias of such multilayer structure as function of electric field at room temperature. Our results show a step forward in utilizing electrically controlled multiferroic systems for practical applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4754842]