GRANULAR THIN-FILM DEPOSITION BY SIMULTANEOUS SPARK EROSION AND SPUTTERING

We have investigated a new method of preparing granular thin films, wh ich are composed of fine metallic particles embedded in a uniform matr ix material. By our method, fine metallic particles are created by spa rk erosion in an inert gas environment and directly deposited onto a c ooled substrate. Magnetron sputtering is employed concurrently thereby building up the matrix. Using such a deposition method, granular thin films are created without the need of any heat treatments and can be made with virtually any material and composition. Furthermore it is ev en possible to create granular thin films from miscible phases. The si ze of the particles can be controlled by varying the pressure under wh ich the spark erosion is conducted up to a few Torr of Ar. We have app lied our method to the case of magnetic particles in a nonmagnetic mat rix. Preliminary transmission electron microscope measurements on Fe p articles in a Cu matrix showed 10-nm-diam. Fe particles. Selected area diffraction patterns show that the film is composed of only the Fe an d Cu phases. Similarly for the Gd-Ag system, 10 nm Gd particles were o bserved in an Ag matrix. Gd-Ag compounds that would be expected to for m were not observed. Magnetic measurements for these systems agreed wi th the nanometer scale microstructure that was observed. (C) 1997 Amer ican Institute of Physics.