Paper on Fe2TiO4 Growth Published in J. Phys.: Cond. Matter

Our team’s latest paper, led by Tiffany Kaspar, has just been published in the Journal of Physics: Condensed Matter! Here we explore the growth of Fe2TiO4 using MBE and high-resolution characterization, evaluating defect formation mechanisms and possible pathways to stabilization of stoichiometric films on MgO.

From the abstract:

Spinel-structure Fe2TiO4 is of interest for its favorable magnetic, catalytic, and electrical transport properties.  Epitaxial thin films of Fe2TiO4 were deposited by molecular beam epitaxy on MgO(001).  The homogeneous incorporation of Ti, Fe valence, and film morphology were all found to be strongly dependent on the oxidation conditions at the low substrate temperatures employed.  More oxidizing conditions led to phase separation into epitaxial, faceted Fe3O4 and rutile TiO2.  Less oxidizing conditions resulted in polycrystalline films that exhibited Ti segregation to the film surface, as well as mixed Fe valence (Fe3+, Fe2+, Fe0).  A narrow window of intermediate oxygen partial pressure during deposition yielded nearly homogeneous Ti incorporation and a large fraction of Fe2+. However, these films were poorly crystallized, and no occupation of tetrahedral sites in the spinel lattice by Fe2+ was detected by x-ray magnetic circular dichroism at the Fe L-edge.  After vacuum annealing, a small fraction of Fe2+was found to occupy tetrahedral sites.  Comparison of these results with previous work suggests that the deposition conditions, restricted to low temperature by the MgO substrate, a path towards obtaining stoichiometric, well-crystallized Fe2TiO4 by MBE by utilizing high substrate temperature and low oxygen partial pressure during deposition on temperature-stable substrates.

To view the manuscript, visit: https://doi.org/10.1088/1361-648X/ac0571

To download the manuscript directly, click here.