The effect of disorder caused by MeV heavy ion irradiation on the tunnel magnetoresistance (TMR) of magnetic tunnel junctions is investigated. Two types of tunnel junctions, viz. Co/Al2O3/Ni80Fe20 and Co/Gd-doped Al2O3/Ni80 Fe20 are studied. Upon 70 MeV Si ion irradiation at a fluence of 5 × 1011 ions/cm2, the undoped junctions show relatively small but irreversible change, while the Gd-doped junctions show a huge reduction, in TMR. In both cases junctions were completely destroyed by 200 MeV Ag ion irradiation at a fluence of 1×1011 ions/cm2. The results are attributed to the modification of the barrier and the neighboring interfaces caused by the high energy density deposited by incident ions.
- SMI-NE: From 2006 in EWI-NE