Epitaxial growth of (111 )-oriented BaTiO_3/SrTiO_3 perovskite superlattices on Pt(111)/Ti/Al_2O_3(0001) substrates

摘要

Symmetric BaTiO_3/SrTiO_3 (BTO/STO) superlattices (SLs) were epitaxially grown on Pt(111)/Ti/ Al_2O_3(0001) substrates with various modulation periods (A = 4.8 - 48 nm) using double ion beam sputter deposition. The BTO/STO SLs exhibit high (111) orientation with two in-plane orientation variants related by a 180° rotation along the [111]_(Pt) axis. The BTO layer is under an in-plane compressive state, whereas the STO layer is under an in-plane tensile state due to the effect of lattice mismaT_ch. A remarkable enhancement of dielectric constant is observed for the SL with relatively small modulation period, which is attributed to both the interlayer biaxial strain effect and the Maxwell-Wagner effect.