Interface engineered BaTiO₃/SrTiO₃ heterostructures with optimized high-frequency dielectric properties.
Interface engineered BaTiO₃/SrTiO₃ heterostructures were epitaxially grown on (001) MgO substrates by pulsed laser deposition. Microstructural characterizations by X-ray diffraction and transmission electron microscopy indicate that the as-grown heterostructures are c-axis oriented with sharp interfaces. The interface relationships between the substrate and multilayered structures were determined to be [001](SrTiO₃)//[001](BaTiO₃)//[001](MgO) and (100)(SrTiO₃)//(100)(BaTiO₃)//(100)(MgO). The high-frequency microwave (∼18 GHz) dielectric measurements reveal that the dielectric constant and dielectric loss of the nanolayered heterostructures are highly dependent upon the stacking period numbers and layer thicknesses. With the increase in the periodic number, or the decrease in each layer thickness, the dielectric constant dramatically increases and the dielectric loss tangent rapidly decreases. The strong interface effect were found when the combination period is larger than 16, or each STO layer is less than 6.0 nm. The optimized dielectric performance was achieved with the best value for the loss tangent (0.02) and the dielectric constant (1320), which suggests that the BTO/STO heterostructures be promising for the development of the room-temperature tunable microwave elements.
Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research,  Xi'an Jiaotong University,  Xi'an 710049, P. R. China.
Ming
M
Liu
Chunrui
C
Ma
Gregory
G
Collins
Jian
J
Liu
Chonglin
C
Chen
Chao
C
Dai
Yuan
Y
Lin
Li
L
Shui
Feng
F
Xiang
Hong
H
Wang
Jie
J
He
Jiechao
J
Jiang
Efstathios I
EI
Meletis
Melanie W
MW
Cole
D017609:Barium Compounds / Q000737:chemistry*; D017097:Electric Impedance; D008872:Microwaves; D010087:Oxides / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
D017609:Barium Compounds; D010087:Oxides; C024547:barium titanate(IV); D014025:Titanium; C119252:strontium titanium oxide; D013324:Strontium