Next generations of magnetic recording will use bit sizes well below one Um ("Ultrahigh Density Recording"). Recently, Betzig et al. (Appl. Phys. Lett. 61, 142(1992)) showed that bits as small as 60nm in diameter could be recorded in Co/Pt multilayers, using a Magneto-Optical Scanning Near field Optical Microscope (MO-SNOM). The work proposed here will bear on this subject. (Pt/F) alloys and multilayers with F= Co, Fe, CoNi, etc..., will be grown using a multitarget sputtering unit on different amorphous or crystalline substrate structures. Samples will be characterized either with conventional means: X ray diffraction, TEM, STM/AFM, magnetometry, magnetooptical Kerr spectroscopy, or using a MO-SNOM currently being developed on the basis of an already operating SNOM with 20nm resolution. Interface and structural properties will be optimized to get perpendicular magnetization, enhanced magnetooptical effects, and a micromagnetic behaviour adapted to the writing of "nano"-bits with minimum wall jaggedness.