Magnetotransport in epitaxial trilayer junctions fabricated from 90° off-axis sputtered manganite films

We report studies on La1-xSrxMnO3 /SrTiO3/ La1-xSrxMnO3 (x=0.33) trilayer junctions made using 90° off-axis sputtering. Both (110) NdGaO3 and (001) (LaAlO3)0.3-(Sr2AlTaO6) 0.7 (LSAT) are used for substrates. Optical lithography is used for junction formation. These sputtered trilayers show improved junction resistance uniformity over trilayers made using laser ablation. A magnetoresistance of ∼100% is observed for junctions on LSAT with 30 Å barrier at 13 K and around 100 Oe. The shape of junction magnetoresistance vs. field depends both on barrier thickness and on substrate type, suggesting that both inter-layer coupling and substrate-induced-strain play a role in determining the junction's micromagnetic state. These results indicate better junction interfaces can be obtained for manganite trilayer junctions by 90° off-axis sputtering.