Large out-of-plane ferroelectric polarization in flat epitaxial BaTiO3 on CoFe2O4 heterostructures
N. Dix, I. Fina, R. Bachelet, L. Fàbrega, C. Kanamadi, J. Fontcuberta, and F. Sánchez
Appl. Phys. Lett. 102, 172907 (2013);
Engineering interfaces in perovskite/spinel heterostructures is challenged by structural differences. We have used kinetic growth limitations to fabricate flat BaTiO3/CoFe2O4 (BTO/CFO) epitaxial bilayers on La2/3Sr1/3MnO3/SrTiO3(001). In situ analysis of lattice strain during growth has revealed that BTO grows relaxed on highly lattice-mismatched CFO, thus suppressing tensile epitaxial stress effects. As a result, BTO is ferroelectric along the out-of-plane direction with bulk-like polarization. These results show that very high lattice mismatch in heteroepitaxy can be an opportunity rather than a limitation to integrate dissimilar materials with optimized functional properties.
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