Epitaxial growth of dielectric Ba0.6Sr0.4TiO3 thin film on MgO for room temperature microwave phase shifters

Abstract

Dielectric Ba0.6Sr0.4TiO3 thin films were epitaxially grown on (001) MgO by using pulsed laser ablation. Microstructure studies from x-ray diffraction and electron microscopy suggest that the as-grown films are c-axis oriented with an interface relationship of 〈100〉BSTO//〈100〉MgO. A room temperature coupled microwave phase shifter has been developed with a phase shift near 250° at 23.675 GHz under an electrical field of 40 V/μm and a figure of merit of ∼53°/dB. The performance of the microwave phase shifter based on the epitaxial Ba0.6Sr0.4TiO3 thin films on (001) MgO is close to that needed for practical applications in wireless communications.

Oxygen exchange kinetics of epitaxial PrBaCo2O5+δ thin films

“…This kinetic model implies that the PBCO film consists of two independent regions with different exchange rates that could correspond to two different film microstructures or two reactions on the highly epitaxial film and surface step terraceinduced antiphase domain boundaries. 15,16 The good agreement confirms the assumption that the kinetics are surface controlled. The surface exchange coefficients were calculated from the two time constants ͑k chem,n = l / n , where l is the thickness of the film͒.…”

Microstructure and dielectric relaxor properties for Ba0.5Sr0.5TiO3/La0.67Sr0.33MnO3 heterostructure

“…Moreover, the typical columnar microstructure in BST film was shown as the dark-bands contrast, which has been also observed in ferroelectric films grown on SrTiO 3 and MgO single crystal. 11,12 As shown in the figure, the presence of an interfacial layer between BST and LSMO layers is not evident. However, its existence cannot be excluded since the presence of such a thin interfacial layer might be faded, due to the charging effect of the dielectric film under electron radiation.…”

Novel Low Temperature Solid State Fuel Cells

“…The columnar-like structure can be clearly observed through the entire film with various domain structures, likely caused by the substrate surface-step-terrace structure. 11 The interface between GCO and YSZ can not be clearly observed.…”