From the 06.05. to the 24.05.2024, I visited the University of Bremen as a guest researcher in the group of Prof. Dr. Thorsten M. Gesing. The central scientific objective of the visit was to perform single crystal X-ray diffraction experiments on Mg and Zr-substituted SrGa₁₂O₁₉ and Sr(Ga,Al)₁₂O₁₉-crystal samples. After a pioneering publication by Mateika and Laurien (1981) on the growth of Mg,Zr:SrGa₁₂O₁₉, the material gained renewed interest at IKZ to be used as substrate for the epitaxial growth of BaFe₁₂O₁₉-thin films. Inducing epitaxial strain onto the thin film enables tuning of the magnitude of the ferroelectric moment of the hexaferrite. To achieve this, we make use of the Sr(Ga,Al)₁₂O₁₉-solid solution system and the decrease in lattice parameter with increasing Al-content to provide substrates with finely tuned lattice parameters suitable for precise strain engineering. The experiments aimed at elucidating the positions of the additives Al, Mg and Zr in the structure. As previous publications did not provide a concise structural model, we attempted to investigate the crystal structure of Sr(Ga,Al)₁₂O₁₉ by means of single crystal XRD.

During the stay, I was able to greatly expand my knowledge on single crystal diffraction, from sample preparation to the correct performance of measurements and data evaluation which will benefit me during the whole duration of my PhD. With the data obtained, I was able to make great progress in tackling the above-mentioned questions regarding the crystal structure of the indeed successfully grown target compound and also assess the quality of the grown material on a structural level.

I would very much like to thank the MAPEX Core Facility for funding and thus making this research stay possible. Furthermore, I extent my great thanks to Prof. Dr. Thorsten M. Gesing and his group for hosting and supporting me for the duration of three weeks. Besides that, they provided a welcoming and very supportive environment to conduct my work. In particular I also have to thank Christopher Reuter for his constant support during my whole stay and teaching me the use of the equipment. Dr. Wilken Seemann always provided his support in all administrative matters and I would very much like to thank him for this as well as his helpful suggestions during the application process.