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This work reports spin transfer switching results on nano-sized MgO-based magnetic tunnel junctions (MTJs) prepared by Ion Beam deposition (IBD). Nano-devices with areas down to 60 nm x 180 nm have been successfully nanofabricated. The MgO deposition conditions were optimized aiming at reducing the resistance-area (RA) product, and RA value as low as 0.8 Ω µm² could be successfully obtained for 0.75 nm thick MgO barriers. The average switching current density of 5.45 x 106 A/cm² can be obtained for a MTJ nanopillar with the dimension of 225 nm x 730.3 nm with low RA of 1.47 Ω µm². [ABSTRACT FROM AUTHOR]

In this paper, junctions with reduced Hf coupling were fabricated by ion beam deposition and oxidation, using CoFeB electrodes. The CoFeB layer has a strong (111) texture that can be the origin of lower Hf and coercivity when compared, with CoFe. Junctions processed down to 2 × 4 μm² with 40-Å-thick CoFeB bottom electrodes have 42% of tunneling magnetoresistance (TMR), (R × A ∼ 400 Ω·μm²), Hc of ∼10 Oe and Hf of ∼2 Oe. CoFe-based junctions (R × A ∼ 500 Ω·μm²) have lower TMR (∼35%) and larger Hf (∼5-6 Oe) and Hc (∼12-14 Oe). Local chemical. composition analysis of the cross section indicated Fe-O segregation with very little Co grown on top of the barrier for CoFe-based junctions and not for CoFeB ones. [ABSTRACT FROM AUTHOR]