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This work focuses on the stability against the oxidation of the chemical, structural, and magnetic properties of the system consisting of a layer of Co tetra-phenyl porphyrins grown on the top of Fe(001) – p(1 × 1)O. Such a system is characterized by a very high degree of structural order and the existence of magnetic coupling between the molecules and the substrate, even at room temperature, as we recently reported [Jagadeesh et al., Appl. Phys. Lett. 115, 082404 (2019)]. We highlight, by using x-ray photoemission spectroscopy, the effect of porphyrins in screening the substrate from oxidation. The coupling between the magnetic response of the system and the order of the molecular layer is investigated by means of spin-resolved UV photoemission spectroscopy and low-energy electron diffraction, respectively. As a result, a link is eventually found between this response and the chemical and structural stability of the interface.

The introduction of a two-dimensional oxide layer at the interface between an organic semiconductor and a ferromagnetic metal (spinterface) can help in tailoring the formation of spin-polarized hybridized interface states. Here, we consider the case of a Cr 4 O 5 monolayer at the C 60 / Fe ( 001 ) interface, which is already known to feature the occurrence of spin-polarized states in the fullerene molecules. In this work, we employ scanning tunneling microscopy/spectroscopy and photoemission spectroscopy to show that the C 60 / Cr 4 O 5 / Fe ( 001 ) spinterface is characterized by the formation of a well-ordered fullerene monolayer and of strongly hybridized interface states. These experimental results are discussed in terms of state-of-the-art ab initio calculations of the structural, electronic, and magnetic properties at the interface.

Reflectance anisotropy spectroscopy (RAS) has been employed to study in situ the growth of thin alpha-sexithiophene films by organic molecular beam deposition onto an organic substrate. A large anisotropy can be detected by following the line shape evolution of the RAS spectrum; in addition, the signal variation at a fixed wavelength is used to monitor the film growth. The signal intensity scales with the deposited thickness, demonstrating a very high sensitivity of RAS to less than 1/50 of a monolayer. Evidence of the advantages of RAS to monitor in real time the growth of molecular films and to probe in situ their properties is therefore obtained. (C) 2003 American Institute of Physics

We investigated the magnetic coupling of ultra-thin Cr films grown at 600 K on a Fe(001)-p(1 × 1)O substrate by means of spin-polarized photoemission spectroscopy. Our findings show that the expected antiferromagnetic stacking of the magnetization in Cr(001) layers occurs right from the first atomic layer at the Cr/Fe interface. This is at variance with all previous observations in similar systems, prepared in oxygen-free conditions, which always reported on a delayed onset of the magnetic oscillations due to the occurrence of significant chemical alloying at the interface, which is substantially absent in our preparation.

Cr ultrathin films have been prepared on the oxygen-passivated Fe(001)-p(1 × 1)O surface, resulting in monolayer range chromium oxide layers. We discuss the presence of first nearest-neighbor Cr pairs, as seen by scanning tunneling microscopy, in the early stages of interface growth and compare the results with previous experimental observations on the Cr/Fe oxygen-free interface. We then derive the magnetic properties of the Cr oxide ultrathin films by analyzing new x-ray magnetic circular dichroism measurements conducted on samples grown both at room temperature and at 400 °C. The ultrathin Cr oxide film forms in both cases a ferromagnetic layer which is antiferromagnetically coupled to Fe. © 2013 AIP Publishing LLC.

In this letter the authors use the evolution of reflectance anisotropy spectra with film thickness during the growth of organic molecular films of a prototype molecular system (α -quarterthiophene grown onto a single crystal of the same material) to demonstrate homoepitaxy. The real time monitoring of the optical anisotropy of a thin film during deposition by organic molecular beam epitaxy is assessed as a powerful tool to achieve an effective in situ control of the growth starting from the very early deposition stages. © 2006 American Institute of Physics.