Growth and electronic and magnetic structure of iron oxide films on Pt(111)

Abstract

Ultrathin (111)-oriented polar iron oxide films were grown on a Pt(111) single crystal either by the reactive deposition of iron or oxidation of metallic iron monolayers. These films were characterized using low energy electron diffraction, scanning tunneling microscopy and conversion electron Mossbauer spectroscopy. The reactive deposition of Fe led to the island growth of Fe 3 O 4 , in which the electronic and magnetic properties of the bulk material were modulated by superparamagnetic size effects for thicknesses below 2 nm, revealing specific surface and interface features. In contrast, the oxide films with FeO stoichiometry, which could be stabilized as thick as 4 nm under special preparation conditions, had electronic and magnetic properties that were very different from their bulk counterpart, wüstite. Unusual long range magnetic order appeared at room temperature for thicknesses between three and ten monolayers, the appearance of which requires severe structural modification from the rock-salt structure. PACS: 68.47.Gh Oxide surfaces, 68.55.-a Thin film structure and morphology, 75.70.Ak Magnetic properties of monolayers and thin films, 81.15.-z Methods of deposition of films and coatings; film growth and epitaxy, 82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods

The nature of the Fe–graphene interface at the nanometer level

“…The Fe film was deposited at RT in UHV and post-oxidized in 1×10 -6 mbar of O 2 at 900 K. 28,29 The film growth was monitored by LEED and STM: the transition of LEED patterns between FeO and multi-layer Fe 3 O 4 ultrathin films occurs at 2 ML nominal FeO coverage, when STM also shows the onset of the growth of Fe 3 O 4 islands. 36,37 One ML of FeO corresponds to 2.16×10 15 Fe atoms/cm 2 .…”

Chemistry-dependent magnetic properties at the FeNi oxide–metal interface

“…The experiments were carried out using the spectroscopic photoemission and low-energy electron microscopy (SPELEEM) instrument at the Nanospectroscopy beamline at Elettra (Trieste, Italy) 32 and a conversion electron Mössbauer spectroscope (CEMS) at the Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences (Krakow, Poland). 12 The SPELEEM instrument combines X-ray photoemission electron microscopy (XPEEM) with low-energy electron microscopy (LEEM). The former provides laterally resolved chemical and magnetic information, whereas the latter is a structural probe mostly applied to crystalline surfaces.…”

“…11 The controlled growth and transformations of the thin film counterparts of these phases were studied by the authors among others. [12][13][14][15][16] Among all the Fe oxide phases, Fe 3 O 4 is the one with the highest interest for magnetic applications, owing to its high Curie temperature and its half-metallic character at RT (room temperature). 11 Hence, Fe 3 O 4 thin films are attractive candidates for incorporation in spintronic devices operating at RT as high-spin-polarized electrodes.…”

The dynamics of Fe intercalation on pure and nitrogen doped graphene grown on Pt(111) probed by CO adsorption

“…Fe was deposited in-situ by physical vapor deposition (PVD); the Fe evaporation rate was determined using as a reference the reconstructions of Fe x O y ultrathin films grown on Pt(111), at increasing Fe coverage. To accomplish this task, the Fe x O y film was deposited at RT in UHV on Pt(111) and post-oxidized in 1×10 -6 mbar of O 2 at 900 K [31,32], and the film growth was monitored by LEED. In the following we adopt the following definition of 1 MLeq Fe: 2.60×10 15 Fe atoms/cm 2 considering its pseudomorphic growth on Pt(111) [33,34].…”