Selectable resistance-area product by dilute highly charged ion irradiation

Considerable effort worldwide has been invested in producing low resistance-area (RA) product magnetic tunnel junction sensors for future hard drive read heads. Here the authors present a method of producing tunnel barriers with a selectable RA value spanning orders of magnitude. A single process recipe is used with only the dose of highly charged ions (HCIs) varied. The HCIs reduce the tunnel barrier integrity, providing enhanced conduction that reduces the overall RA product. The final RA product is selected by appropriate choice of the HCI density; e.g., 100 HCIs/mu m(2) typically results in the RA product being reduced by a factor of 100. (C) 2007 American Institute of Physics.