Atomic scale description of SrTiO3|SrRuO3 interfaces and the effect on the magnetic arrangements

The strontium ruthenate (SrRuO₃) is a ferromagnetic material that has been widely studied in the last fifty years due to its high conductivity. On the other hand, the strontium titanate (SrTiO3) is a paraelectric semiconductor that has been studied due to its high-energy storage and photocatalytic applications. Motivated by the experimental findings, in this work, we investigate the SrTiO3/SrRuO3 interfaces at the atomic scale. Eight different models were employed to investigate the interface, considering different surface terminations of the SrTiO3 and SrRuO3. The interface formation energy formalism was employed to study the thermodynamic stability of the models. The theoretical results are consistent with experimental ones. The interfaces were synthesized via pulsed laser deposition (PLD) and characterized using atomic force microscopy (AFM), X-ray diffraction (XRD), among others. The XRD analysis revealed the growth of orthorhombic SrRuO3 onto cubic SrTiO3 . Our proposed atomistic model fits perfectly with the structure obtained in experiments. Besides, we analyzed the magnetic properties of the interface, the SrTiO3 acquires a very small induced magnetization, and at the most exposed layers of the SrRuO3 the magnetization is reduced when compared with the bulk system, this is due to surface effects, which has been confirmed with experimental results. Finally, the magnetic anisotropy of the SrRuO3 was analyzed to determine if the growth direction influences the easy magnetization axis.