title: Monte Carlo simulation of segregation in ceramic thin films.
abstract: A Monte Carlo exchange technique is used to study segregation in thin ceramic films with application to MgO/MnO. The approach is not restricted to the dilute limit. Surface concentrations as a function of temperature and film composition are determined directly from the simulations. For all compositions studied (Mn(chi)Mg(1-chi)O, 0 < or = chi < or = 1) the (001) surface is Mn(2+) rich; the occupancy of sites by Mn(2+) decreases rapidly with depth. The ratio of the number of Mn(2+) to Mg(2+) ions at the surface decreases as a function of temperature. The calculated enthalpies of segregation of Mn(2+) for the thin film are strongly dependent on the total Mn(2+) concentration at small Mn(2+) concentrations, with the enthalpy of segregation varying by a factor of two with surface coverage.
authors.affiliation: CCLRC, Daresbury Laboratory, Warrington, UK WA4 4AD. j.a.purton@dl.ac.uk
authors.forename: John A
authors.initials: JA
authors.lastname: Purton
authors.forename: Mikhail Yu
authors.initials: MY
authors.lastname: Lavrentiev
authors.forename: Neil L
authors.initials: NL
authors.lastname: Allan
authors.forename: Ilian T
authors.initials: IT
authors.lastname: Todorov
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D008567:Membranes, Artificial; D009010:Monte Carlo Method; D013499:Surface Properties; D013696:Temperature
chemical_list: D008567:Membranes, Artificial; D008345:Manganese; D008274:Magnesium