0000000000078301
AUTHOR
Florencio Sánchez
Domain structure of epitaxial SrRuO3 thin films
Growth of multidomains in epitaxial thin-film oxides is known to have a detrimental effect on some functional properties, and, thus, efforts are done to suppress them. It is commonly accepted that optimal properties of the metallic and ferromagnetic $\mathrm{SrRu}{\mathrm{O}}_{3}$ (SRO) epitaxies can only be obtained if vicinal $\mathrm{SrTi}{\mathrm{O}}_{3}$ (001) (STO) substrates are used. It is believed that this results from the suppression of multidomain structure in the SRO film. Here we revise this important issue. Nanometric films of SRO have been grown on STO(001) vicinal substrates with miscut $({\ensuremath{\theta}}_{V})$ angles in the $\ensuremath{\sim}0.04\ifmmode^\circ\else\te…
The Poisson Ratio in CoFe2O4Spinel Thin Films
The response of epitaxial CoFe2O4 thin films to biaxial compressive stress imposed by MgAl2O4 and SrTiO3 single crystalline substrates is studied using X-ray diffraction and Raman spectroscopy. It is found that the Poisson ratio ν signals a non-auxetic behavior and depends on the substrate used. The Raman modes show an increase in frequency when increasing compressive strain by reducing film thickness; this is due to the shrinking of the unit cell volume. Such behavior is in qualitative agreement with recent ab initio calculations, although the measured values are significantly smaller than predictions. In contrast, the measured Poisson ratio is found to be in good agreement with expectatio…