Fabrication of magnetic SmFe films by pulsed laser deposition at 157 nm

By applying a pulsed laser deposition (PLD) technique with a 157-nm molecular fluorine laser, in a novel ablative geometry, nanocrystalline magnetic films were fabricated for the first time to our knowledge from solid Sm/sub 13.7/ Fe/sub 86.3/ targets with 25-mJ laser energy per pulse in 1-atm He background pressure, which is at least one order of magnitude lower than the energy at 248 nm with a KrF laser. The coercivity of the films after annealing at 680/spl deg/C was 0.1 T; in the case when films were fabricated at high vacuum (10/sup -5/ mbar), we did not observe any coercivity, and films were deposited together with ablated droplets of different size, the presence of which reduces the magnetic properties of the films. In both cases the films were deposited on a Si wafer coated with a /spl sim/150-nm-thick Ta layer. At 157 nm, the composition of the magnetic films remains the same as the initial target composition when at 248 nm the ratio of iron to rare earth on the film is higher than on the target.