title: Phase stabilization in nitrogen-implanted nanocrystalline cubic zirconia.
abstract: The phase stability of nanocrystallites with metastable crystal structures under ambient conditions is usually attributed to their small grain size. It remains a challenging problem to maintain such phase integrity of these nanomaterials when their crystallite sizes become larger. Here we report an experimental-modelling approach to study the roles of nitrogen dopants in the formation and stabilization of cubic ZrO(2) nanocrystalline films. Mixed nitrogen and argon ion beam assisted deposition (IBAD) was applied to produce nitrogen-implanted cubic ZrO(2) nanocrystallites with grain sizes of 8-13 nm. Upon thermal annealing, the atomic structure of these ZrO(2) films was observed to evolve from a cubic phase, to a tetragonal phase and then a monoclinic phase. Our X-ray absorption near edge structure study on the annealed samples together with first-principle modelling revealed the significance of the interstitial nitrogen in the phase stabilization of nitrogen implanted cubic ZrO(2) crystallites via the soft mode hardening mechanism.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors.forename: Gonghua
authors.initials: G
authors.lastname: Wang
authors.forename: Guangfu
authors.initials: G
authors.lastname: Luo
authors.forename: Yun Liang
authors.initials: YL
authors.lastname: Soo
authors.forename: Renat F
authors.initials: RF
authors.lastname: Sabirianov
authors.forename: Hong-Ji
authors.initials: HJ
authors.lastname: Lin
authors.forename: Wai-Ning
authors.initials: WN
authors.lastname: Mei
authors.forename: Fereydoon
authors.initials: F
authors.lastname: Namavar
authors.forename: Chin Li
authors.initials: CL
authors.lastname: Cheung
mesh_terms: D018360:Crystallography, X-Ray; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry*; D044367:Phase Transition; D011789:Quantum Theory; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015040:Zirconium; D009584:Nitrogen; C028541:zirconium oxide