Ultrathin Fe-oxide layers made from Langmuir–Blodgett films

• Published in: Thin solid films 1999-01, Vol.338 (1), p.231-242
• Main Authors: Brugger, A., Schoppmann, Ch, Schurr, M., Seidl, M., Sipos, G., Hahn, C.Y., Hassmann, J., Waldmann, O., Voit, H.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Iron oxide; Langmuir-blodgett films; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Monolayers; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)00955-9

Thin Fe-oxide films (15–150 nm thick) have been prepared using Langmuir–Blodgett (LB) films as precursors consisting of a certain number of Fe–arachidate monolayers (ML). The organic component of the LB films was removed by different heating procedures: heating in ambient air at 360 and 900°C, and at 500°C in a H 2 gas flow. The remaining Fe-oxide films were analyzed by a number of methods. The most important results are: all Fe-oxide films are smooth and homogeneous (roughnesses between 0.8 and 4 nm), the magnetic properties are, however, not sufficient for an application as magnetic storage medium. Only a film prepared from 35 ML Fe–arachidate by heating at 500°C in H 2 had magnetic properties (hysteresis loop of the single domain type, large coercivity and saturation magnetization) suited to use the film as a high data density magnetic storage medium. The films heated at ambient air consist mainly of α-Fe 2O 3. In addition they contain most probably γ-Fe 2O 3 and Fe 3O 4 (films heated at 360°C) or Fe 3O 4 and FeO (films heated at 900°C). Films heated in H 2 consist of Fe 3O 4, FeO and metallic α-Fe.