Effects of SrRuO₃ on properties of functional oxide heterostructures

SrRuO₃ is a ferromagnetic metallic oxide and is often used as an electrode material for epitaxial ferroelectric heterostructures. We fabricated SrRuO₃/PbZr_0.2Ti_0.8O₃/SrRuO₃ and SrRuO₃/La_0.7Ba_0.3MnO₃/SrRuO₃ tri-layers on SrTiO₃(100) by PLD. Atomic resolution TEM showed that the first 3 unit cells of the ferroelectric PbZr_0.2Ti_0.8O₃ layer have a reduced polarization, indicating that the bottom SrRuO₃ layer may not be the best electrode for ferroelectric tunnel junctions. However, ferromagnetic properties of 2 unit cells thick La_0.7Ba_0.3MnO₃ layers interfaced with SrRuO₃ layers are much improved.