Strain manipulation in BaTiO3/SrTiO3 artificial lattice toward high dielectric constant and its nonlinearity

Enhancement of dielectric properties has been demonstrated in BaTiO3 (BTO)/SrTiO3 (STO) strained artificial lattice. Large variation of lattice distortion in the consisting BTO and STO layers was achieved by varying a stacking sequence of BTO and STO layers. From this strain manipulation, it is found that BTO and STO lattices have a dielectric constant sensitively influenced by the lattice distortion and, more importantly, maximum dielectric constant at a certain degree of lattice distortion. An appropriate degree of lattice distortions of the consisting layers is needed to obtain the large dielectric constant and its nonlinearity of the artificial lattice. The artificial lattice exhibited the large dielectric constant (1230) and extremely large nonlinearity (94%) at the periodicity of BTO2 unit cell/STO2 unit cell. These results suggest that the strain is a macroscopically important factor to influence the dielectric properties and can be manipulated via oxide artificial lattice to obtain large dielectric constant and its nonlinearity. (C) 2003 American Institute of Physics.