Co growth on Pt(997): from monatomic chains to monolayer completion

We have used the Pt(997) surface as a deposition template to grow high-dens ity arrays (5 x 10(6) cm(-1)) of parallel Co nanowires. We demonstrate that we can routinely grow ordered arrays of single monatomic chains of Co with precise coverage monitoring by in situ thermal energy atom scattering (TEA S). Nanowires constituted by one or more atomic chains have been characteri zed as a function of the substrate temperature and coverage by TEAS and sca nning tunneling microscopy (STM). We find that, due to slow edge diffusion at low temperature and interlayer mass transport at high temperature, perio dic arrays of uniform smooth chains are obtained only between 250 and 300 K . Co deposition in this temperature range results in a uniform coverage of chains having the same average width that can be used to investigate the ma gnetic properties of one-dimensional structures. The structure of a single- layer Co him has also been investigated: we show that the Co monolayer deve lops a non-periodic dislocation network upon deposition at 250 K. There is evidence for moderate Co incorporation into the first Pt layer below room t emperature. (C) 2000 Elsevier Science B.V. All rights reserved.