Magnesium interdiffusion and surface oxidation in magnetite epitaxial films grown on MgO(1 0 0).

Magnetic Properties of Fe3O4Films on Fe(001)

“…The Mössbauer spectrum shown in Fig. 1a, similar to that obtained in previous experiments [2,5], is characteristic of superparamagnetic (spm) relaxation. The spectrum was fitted using the Blume-Tjon model [12] of relaxation, including a narrow distribution of the fluctuation frequency and averaged hyperfine parameters of magnetite (hyperfine magnetic field B hf = 46.0 T and isomer shift IS = 0.36 mm/s).…”

“…The presence of APBs strongly influences the magnetic properties of magnetite. Most of all, Fe 3 O 4 ultrathin films show superparamagnetic behaviour [2,5], which is the most critical effect hindering potential applications of ultrathin magnetite films. Furthermore, antiferromagnetic coupling between antiphase domains across the APBs results in a higher saturation magnetic field observed for thin magnetite films as compared to the bulk crystal [1,6], and consequently, despite the magnetic shape anisotropy, the local magnetic moments in the Fe 3 O 4 layers are not oriented in the film plane [2,6].…”

Size effects in epitaxial films of magnetite

“…Below Tv the M6ssbauer spectrum becomes compliIn this paper we present resent results concerning cated and difficult to interpret, comprising a superposiFe 3 0 4 (001) films grown by reactive deposition on tion of at least five components. Any impurities and MgO(001) substrates [24,25] as well as obtained by a vacancies screen the hopping process, lowering the post-preparation oxidation of epitaxial Fe(001) films transition temperature and changing the character of the [26]. Combination of STM and CEMS studies applied transition.…”

“…To structure of magnetite will be discussed in more detail clarify this problem the GEMS measurements were done below, in relation to STM measurements. Here we want for the 10 nm Fe 3 0 4 (001) film after 1-month exposure only to stress the obvious difference between the both to the atmosphere and then again at UHV condition, spcr.Frte( -2R5rcotutinthse-after being annealed in vacuum for 1 h at 600 K [25].…”

“…The UHV condition is Fe diffuses into MgO, finally forming a Fe, -,O wustite-1000 K, with 100 K steps, for the 60 nm epitaxial magnetite film type oxide with the cubic structure of MgO [36]. For [25].…”