The study of preparation of SrAl₁₂O₁₉ thin films

R. Uhrecký¹, J. Buršík¹, R. Kužel²

¹Institute of Inorganic Chemistry of the AS CR, v.v.i., Husinec-Řež.p. 1001, CZ-25068 Řež, č.p. 1001,
uhrecky@iic.cas.cz

Hexagonal ferrites thin films based on iron (III) oxides have attracted great interest in the field of magnetic oxide materials. They are used as information storage medium and in diverse microwave applications. In order to improve their functional properties through improved crystallographic and magnetic anisotropy, buffer layers that match structural and chemical properties of ferrite film and substrate materials are frequently used in the growth technology. Hexagonal aluminate with formula SrAl₁₂O₁₉ is suitable material as buffer layer due to its chemical stability and low lattice misfits parameters against Al₂O₃ substrate and magnetic hexagonal ferrites.

In our work we studied preparation of a non-magnetic SrAl₁₂O₁₉ thin film prepared by chemical solution deposition CSD method on Al₂O₃ (0001) substrate. SrAl₁₂O₁₉ thin films were prepared in two different ways, i.e. (a) by direct deposition of SrAl₁₂O₁₉ sol on Al₂O₃ (0001) substrate, or (b) in situ reaction of SrO sols with Al₂O₃ substrate. Prepared films were studied by XRD diffraction and by AFM measurements.

Both approaches lead to the formation of highly oriented 000l SrAl₁₂O₁₉ thin films. Detailed XRD studies of films show significant differences between both processes. Direct deposition of SrAl₁₂O₁₉ sols lead to the dense film with hexagonal structure. According XRD analysis, these structures show several in-plane orientation variants.

Layers prepared by solid state reaction between SrO with Al₂O₃ substrate show only one in-plane orientation of SrAl₁₂O₁₉.The final film contains sparse columnar hexagonal islands and these islands contain probably different Sr-Al-O phases or unreacted SrO at lower temperatures.

 

 

 

 

This study was supported by Grant agency of Czech Republic GA14-18392S.