<i>In situ</i> x-ray measurements of the initial epitaxy of Fe(001) films on MgO(001)

Lairson, B. M.; Payne, A. P.; Brennan, S.; Rensing, N. M.; Daniels, Brian; Clemens, B. M.

doi:10.1063/1.359853

Cited by 61 publications

(18 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…48 Fe growth on MgO is a three-dimensional island mode. 49 However, in the case of the bottom electrode, the Fe layer is thick ͑50 or 100 nm͒ and undergoes thermal annealing, which results in an epitaxial and smooth layer.…”

Section: Growth Modes Of the Electrode And Barriermentioning

confidence: 99%

Structural characterization of interfaces in epitaxial Fe/MgO/Fe magnetic tunnel junctions by transmission electron microscopy

et al. 2010

View full text Add to dashboard Cite

We present a detailed structural characterization of the interfaces in Fe/MgO/Fe layers grown by molecularbeam epitaxy using aberration-corrected transmission electron microscopy ͑TEM͒, scanning TEM, and electron energy-loss spectroscopy. When fabricated into magnetic tunnel junctions, these epitaxial devices exhibit large tunnel magnetoresistance ratios ͑e.g., 318% at 10 K͒, though still considerably lower than the values predicted theoretically. The reason for this discrepancy is being debated and has been attributed to the structure of, and defects at the interface, namely, the relative position of the atoms, interface oxidation, strain, and structural asymmetry of the interfaces. In this structural study, we observed that Fe is bound to O at the interfaces. The interfaces are semicoherent and mostly sharp with a minor degree of oxidation. A comparison of the two interfaces shows that the top MgO/Fe interface is rougher.

show abstract

Section: Growth Modes Of the Electrode And Barriermentioning

confidence: 99%

Structural characterization of interfaces in epitaxial Fe/MgO/Fe magnetic tunnel junctions by transmission electron microscopy

et al. 2010

View full text Add to dashboard Cite

show abstract

“…However, from an experimental point of view, it is not straightforward to obtain a continuous, monolayer thick Fe film that fully covers the substrate to test these predictions, due to the formation of disconnected Fe islands several atoms thick in the first stages of growth. 4,5 As a consequence, no giant magnetic moment has been experimentally found in this system so far. 4,6 The reduction of the physical dimensions is likely to modify the electronic structure of the materials and therefore their magneto-optical activity.…”

Section: Introductionmentioning

confidence: 99%

Coverage effects on the magnetism ofFe∕MgO(001)ultrathin films

Boubeta¹,

Clavero²,

García-Martín³

et al. 2005

Phys. Rev. B

View full text Add to dashboard Cite

Different aspects of the structure-magnetism and morphology-magnetism correlation in the ultrathin limit are studied in epitaxial Fe films grown on MgO(001). In the initial stages of growth the presence of substrate steps, intrinsically higher than an Fe atomic layer, prevent the connection between Fe islands and hence the formation of large volume magnetic regions. This is proposed as an explanation to the superparamagnetic nature of ultrathin Fe films grown on MgO in addition to the usually considered islanded, or Vollmer-Weber, growth. Using this model, we explain the observed transition from superparamagnetism to ferromagnetism for Fe coverages above 3 monolayers (ML). However, even though ferromagnetism and magnetocrystalline anisotropy are observed for 4 ML, complete coverage of the MgO substrate by the Fe ultrathin films only occurs around 6 ML as determined by polar Kerr spectra and simulations that consider different coverage situations. In annealed 3.5 ML Fe films, shape or configurational anisotropy dominates the intrinsic magnetocrystalline anisotropy, due to an annealing induced continuous to islanded morphological transition. A small interface anisotropy in thicker films is observed, probably due to dislocations observed at the Fe/ MgO͑001͒ interface.

show abstract

“…The Fe atoms are sitting above the O 2À sites on the MgO(1 0 0) surface [2,5]. First, round shaped islands of different sizes are formed at room temperature deposition [14,[17][18][19][20][21][22][23]. The epitaxially grown Fe films have a small contraction of the vertical lattice constant to compensate for the in plane expansion imposed by the lattice mismatch between MgO and Fe.…”

Section: Discussionmentioning

confidence: 99%