Title :
Ion beam deposition and oxidation of spin-dependent tunnel junctions
Author :
Cardoso, Susana ; Gehanno, Véronique ; Ferreira, Ricardo ; Freitas, Paulo P.
Author_Institution :
INESC, Lisbon, Portugal
fDate :
9/1/1999 12:00:00 AM
Abstract :
Spin dependent tunnel junctions showing tunnel magnetoresistance (TMR) values of 39~41% were fabricated using Ion Beam Deposition (IBD). Both the electrodes and the aluminum layer deposition were done by IBD. The aluminum oxidation was performed using the assist gun with an oxygen beam (+30 V acceleration voltage applied on the grids) using mixed O2/Ar plasma. The oxidation was monitored in real time with a residual gas analyzer (RGA). The junction area is defined by lithography, down to 3×2 μm2. As-deposited junctions with 15 Å of Al showed TMR of 27~29%, independent of the junction area, with resistance-area products of 0.8~1.6 MΩ×μm2. This TMR value reached 40% upon annealing at 290°C, with resistance decreasing to 0.5~0.8 MΩ×μm2
Keywords :
alumina; aluminium; annealing; giant magnetoresistance; interface magnetism; ion beam assisted deposition; oxidation; plasma materials processing; tunnelling; vacuum deposition; 15 A; 2 mum; 290 C; 3 mum; Al; Al2O3; Ar; O2; aluminum layer deposition; annealing; electrodes; ion beam deposition; lithography; mixed O2/Ar plasma; oxidation; residual gas analysis; resistance-area products; spin-dependent tunnel junctions; tunnel magnetoresistance; Acceleration; Aluminum; Argon; Electrodes; Ion beams; Oxidation; Particle beams; Plasma accelerators; Tunneling magnetoresistance; Voltage;
Journal_Title :
Magnetics, IEEE Transactions on
