Suppression of exchange bias by ion irradiation

The exchange bias effect in ferromagnetic/antiferromagnetic sandwich struct ures is generally believed to be sensitive on the interface exchange intera ction, the magnetization, and the thickness of the ferromagnetic layer. Als o the interface structure plays a crucial role. We show that, by irradiatin g samples with He ions, we can manipulate the exchange bias field in a cont rolled manner. Depending on the dose (10(14)-10(17) ions/cm(2)) and the acc eleration voltage (10-35 kV) of the ions, the shift of the hysteresis can b e reduced or even fully suppressed. Potential applications of this effect f or magnetic patterning on the nanoscale will be discussed. (C) 2000 America n Institute of Physics. [S0003-6951(00)03608-1].