Growth, structure, and magnetism of fcc Fe ultrathin films on Cu(111) by pulsed laser deposition

Abstract

Ultrathin Fe films on Cu͑111͒ have been grown by pulsed-laser deposition ͑PLD͒ whose instantaneous deposition rate is about six orders of magnitude larger than that of the conventional molecular-beam epitaxy based on thermal deposition ͑TD͒. Compared to the TD prepared Fe/Cu͑111͒ films, the PLD films have a significantly improved layer-by-layer morphology and a substantially enhanced stability of the fcc phase as characterized by scanning tunneling microscopy and electron-diffraction techniques. The magnetic properties of the PLD films, investigated by magneto-optical Kerr effect, also show remarkably different behavior as compared to the TD films. At low thickness ͑Ͻ3 ML͒, while the TD films are characterized by a low net moment and a short-range ferromagnetic order, the PLD films show a high net moment with a true long-range ferromagnetic order. Above 3 ML both PLD and TD films undergo a magnetic transition though with apparently different structural origin. We discuss these results based on the different growth and structure between the PLD and TD grown Fe films.

Comparison of morphology evolution of Ge(001) homoepitaxial films grown by pulsed laser deposition and molecular-beam epitaxy

“…A question naturally arises: can we understand PLD in light of well-known MBE paradigm? There have been some theoretical 9,10 and experimental 11,12 studies comparing these two growth techniques in attempting to answer this question. The results of experimental studies are so sensitive to deposition conditions that it is crucial to compare the results from these two techniques under identical conditions 12 : same temperature calibration, background pressure, sample preparation, etc.…”

Atom-probe study of Cu and NiAl nanoscale precipitation and interfacial segregation in a nanoparticle-strengthened steel

“…From the nucleation point of view, the interfacial energy and strain energy play an important role in the formation of nanoparticles in a supersaturated solid solution [10]. The lattice constants of fcc-Cu and fcc-Fe are 3.61 and 3.65 nm [25], respectively. The very small difference between their lattice constant leads to a very small strain energy and, hence, favors a coherent interface between the fcc Cu nanoparticles and austenite matrix.…”

Investigation of the structure of ultra-thin films of Fe on Cu(111) using medium-energy ion scattering

“…The energy-scanned photoelectron diffraction [7] measurements, however, reported an abrupt transformation with the entire film converting to bcc. In contrast, STM images [10] show bright needle like areas that are considered to be needle like domains of bcc Fe sitting on fcc Fe.…”

“…It is widely reported that Fe grows in a pseudomorphic fcc structure for the first few monolayer equivalents. Some LEED/AES investigations reported layer-by-layer growth [3,4], but angle-scanned photoelectron diffraction [5] and STM [10] measurements have shown that the Fe grows in 3-D islands and that the initial islands are mostly of bilayer height.…”

“…It has been studied by low energy electron diffraction (LEED) [3,4,5,6], angle-scanned photoelectron diffraction [5], energy-scanned photoelectron diffraction [7], scanning tunnelling microscopy (STM) [8,9,10,11], surface EXAFS [12] and normal incidence X-ray standing wave [13]. It is widely reported that Fe grows in a pseudomorphic fcc structure for the first few monolayer equivalents.…”