Effect of ion irradiation on the characteristics of magnetic tunnel junctions
MESA Institute for Nanotechnology,
University of Twente, 7500 AE Enschede, The Netherlands
2 Francis Bitter Magnet Lab, MIT, 170 Albany Street, Cambridge, MA02139, USA
3 Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, Orissa, India
4 Nuclear Science Centre, Aruna Asaf Ali Marg, New Delhi 110 067, India
Corresponding author: T.Banerjee@ewi.utwente.nl
Revised: 19 July 2005
Accepted: 20 July 2005
Published online: 26 October 2005
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/Ni80Fe20 are studied. Upon 70 MeV Si ion irradiation at a fluence of 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 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.
PACS: 61.80.Jh – Ion radiation effects / 85.30.Mn – Junction breakdown and tunneling devices (including resonance tunneling devices) / 85.70.Kh – Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
© EDP Sciences, 2005