Study of the crystal structure, phase composition and magnetic properties of textured magnetite films grown by reactive deposition

The study of magnetic films grown on the oxidized silicon surface is of interest from the point of view of creating “ferromagnetic metal/dielectric” tunnel contacts and implementing the transport of spin-polarized electrons. In this work, textured polycrystalline magnetite films were prepared by reactive deposition of iron onto a SiO$_2$/Si(001) surface under a molecular oxygen atmosphere. Films with a thickness of 15–250 nm were studied using Raman spectroscopy and X-ray diffraction. From the analysis of experimental data, it was established that as a result of reactive deposition, magnetite crystallites grow predominantly in two orientations – (311) and (100). The crystallite lattice constant does not depend on the film thickness, but its value is $\sim$1% less than for single-crystal magnetite. Studies of magnetic properties have shown that the magnetic behavior of samples greatly changes its character in samples with a magnetite film thickness of less than 70 nm.