We show that atomically flat single SrO-terminated ${\text{SrTiO}}_3\left(001\right)$ substrates can be obtained through simple high-temperature treatment. Amplitude-modulation atomic force microscopy with phase-lag analysis and x-ray photoelectron spectroscopy, have been used to demonstrate that the ratio between the two chemical terminations can be tailored by choosing the annealing time. Moreover, the progressive SrO surface enrichment (up to 100%) is accompanied by a self-assembly process which results in the spatial separation at the nanoscale of both chemical terminations. We further demonstrate that this opens a interesting avenue for selective chemical reaction and growth of oxide nanostructures.

Magnetic and structural characteristics of $\mathrm{Er}\mathrm{Fe}{\mathrm{O}}_3$ , $\mathrm{Tm}\mathrm{Fe}{\mathrm{O}}_3$ , and $\mathrm{Yb}\mathrm{Fe}{\mathrm{O}}_3$ single crystals were studied over a wide temperature range. Magnetic measurements found that the spin-rotation transitions in all crystals are well described by the earlier proposed theory with no fitting parameters. Additionally, they have shown the absence of the magnetic compensation point in $\mathrm{Tm}\mathrm{Fe}{\mathrm{O}}_3$ and a noticeable growth of the $c$ -axis magnetization at low temperatures in $\mathrm{Tm}\mathrm{Fe}{\mathrm{O}}_3$ and $\mathrm{Er}\mathrm{Fe}{\mathrm{O}}_3$ . The x-ray measurements found no symmetry-lowering lattice distortions during the reorientation. Overall, the measurements cover a wide range of material parameters and demonstrate the generality of the modified mean field theory of the ${\Gamma }_4\to {\Gamma }_{24}\to {\Gamma }_2$ orientation phase transitions in orthoferrites.