Properties of a Co/Cu/Co spin-valve system prepared by an optimized 193 nm pulsed laser deposition process

摘要

Layered CoO/Co(7 nm)/Cu(6 nm)/Co(7 nm) spin-valve systems capped by a 5 nm boron top layer, which exhibit giant magnetoresistance (GMR), were prepared by pulsed laser deposition (PLD) with a 193 nm ArF excimer laser. To reduce atomic intermixing at the various layer interfaces, the areal energy density of the laser was lowered to 4.2 J/cm~2 for the first 2 nm of the intermediate Cu and the Co top layers, while applying 11 J/cm~2 for the rest. By this procedure, a clear improvement of the GMR could be accomplished as compared to an identical reference system prepared by exclusively applying the high value of 11 J/cm~2, pointing to the importance of minimizing interface mixing. Additionally, the effect of the laser intensity on the areal density and shape of μm-sized droplets co-deposited onto the substrates by PLD was studied. It turned out that for the two limiting values applied in the present case, no negative influence of the droplets on the magnetic hysteresis of pure Co layers or spin-valve systems could be observed.