Formation mechanism and physical properties of a magnetic thin film system deposited on liquid substrates

An almost freely sustained new iron film system deposited on a silicone oil surface by vapor phase deposition has been fabricated, and its growth mechanism, internal stress patterns and low temperature magnetic properties have been studied. It is found that the growth mechanism obeys the two-stage growth model which was construed for non-magnetic film systems on liquid substrates. At a fixed substrate temperature and low deposition rate the iron films are almost transparent, and large ordered crack patterns with a characteristic length on the order of 10E2 μm are observed. Experiment shows that the ordered patterns result from the extrusion and alternate insertion of different pieces of iron film, due to the internal stress released in the nearly freely sustained film system. For higher deposition rates, however, the iron films exhibit a normal metallic color and the temperature dependence of the coercivity Hc (T)of the films has a marked maximum peak around the critical temperature Tc = 10—15 K. Our experimental results show that the anomalous magnetic properties are due to the non-uniform particle size distribution, random surface anisotropy and interparticle interactions in the films.