| AVS 62nd International Symposium & Exhibition | |
| Thin Film | Friday Sessions |
| Session TF+MI-FrM |
| Session: | Thin Films for Light Trapping, Plasmonic, and Magnetic Applications |
| Presenter: | Radomir Kuzel, Charles University in Prague, Czech Republic |
| Authors: | R. Kuzel, Charles University in Prague, Czech Republic J. Bursik, Academy of Sciences of the Czech Republic M. Soroka, Academy of Sciences of the Czech Republic K. Knizek, Academy of Sciences of the Czech Republic |
| Correspondent: | Click to Email |
Different kind of thin films with remarkable magnetic and magnetoeletric properties require strong preferred orientation in order to utilize strong anisotropy of their properties.
The main aim of the work is to prepare the films of hexagonal ferrites showing magnetoelectric effects. There are several types of these materials marked as e.g. M-type [(Ba,Sr)Fe12O19, space group P63/mmc], Y-type [(Ba,Sr)2Me2Fe12O22, s. g. R-3m], Z-type [(Ba,Sr)3Me2Fe24O41, s. g. P63/mmc], and others. Our attention was focussed mainly to Y-type where the best properties are expected. All these lattices are long along c-axis and this should be oriented perpendicular to the surface. The films were prepared through the chemical solution method either on SrTiO3 (111) or sapphire Al2O3 (0001) substrates, respectively. We are looking not only for suitable substrates but also we have succeeded in using seed template interlayers, for example M hexaferrite SrFe12O19. A detailed inspection revealed that growth of seed layers starts through the break-up of initially continuous film into isolated grains with expressive shape anisotropy and hexagonal habit. Promising type of such seed layers seem also to be SrAl12O19 films where two kinds of preparation were investigated – deposition of SrAl12O19 onto sapphire substrate and reaction SrO + Al2O3.
Other type of magnetic films studied were magnetic spinels Co3O4 prepared by decomposition of films of layered cobaltates NaxCoO2 deposited by chemical solution deposition method and grown on sapphire substrates.
The films were characterized mainly by AFM and by several XRD techniques. Phase transitions and thermal stability were studied in symmetric Bragg-Brentano geometry, degree of preferred orientation by rocking curves (omega scans) and phi scans of asymmetric reflections, pole figures and also by reciprocal space maps. Residual stresses were also tested but they were usually zero or negligible. All the films were strongly oriented with the planes parallel to the surface but different kind of in-plane orientations was observed often structures with with several domains.