Postannealing of magnetic tunnel junctions with ion-bombardment-modified exchange bias

Höink V, Sacher M, Schmalhorst J-M, et al. Postannealing of magnetic tunnel junctions with ion-bombardment-modified exchange bias. APPLIED PHYSICS LETTERS. 2005;86(15): 152102.The influence of a postannealing procedure on the transport properties of magnetic tunnel junctions with ion-bombardment-manipulated exchange bias is investigated. The controlled manipulation of the direction of the exchange bias field in magnetic tunnel junctions by He ion bombardment usually is accompanied by a reduction of the tunneling magnetoresistance and an increase in the resistance. Here, we demonstrate that it is possible to reduce these negative effects of the ion bombardment considerably by postannealing without a magnetic field. For optimized combinations of ion dose and postannealing temperature, the tunneling magnetoresistance recovers completely (>50% resistance change) while the exchange bias direction set by the ion bombardement is preserved. (C) 2005 American Institute of Physics