SrAl12O19 thin films by chemical solution deposition and their use as buffer layers for oriented growth of hexagonal ferrites

Publication date: 1 October 2016
Source:Thin Solid Films, Volume 616
Author(s): Josef Buršík, Róbert Uhrecký, Dorota Kaščáková, Radomír Kužel, Václav Holý, Milan Dopita
Thin films of SrAl12O19 were prepared on α-Al2O3(0001) substrates through the chemical solution deposition method and thermal treatment. Two types of precursor systems were used: stoichiometric mixture of strontium methoxyethoxide with aluminium iso-butoxide, and strontium methoxyethoxide topotactically reacting with Al2O3 substrate. Two distinctly different film-substrate orientation relationships were observed. In the latter case the orientation can described as perfect hexagon-on-hexagon epitaxy with $\left(11\stackrel{-}{2}0\right)$ SrAl12O19 || $\left(10\stackrel{-}{1}0\right)$ Al2O3 and (0001)Al2O3 || (0001)SrAl12O19. This relationship has 1.17% lattice misfit in the substrate plane. In the former case SrAl12O19 grains are rotated about the substrate normal and form more orientation variants that can be explained by the coincident-site lattice model for grain boundaries. We demonstrated that both types of SrAl12O19 films can be used as a chemical buffer and structural template layer for the growth of oriented hexagonal ferrite thin films. In both types of films the (BaSr)Fe12O19 phase cope the in-plane orientation of their respective templates.