Figure  5a shows the frequency dependence of the relative dielectric constant and the loss tangent

for the multilayer. The relative dielectric constant and the loss tangent are varying from 340 to 445 and from 0.001 to 0.04, respectively. A maximum dielectric constant of approximately 445 at 10.65 GHz and a minimum dielectric loss of approximately 0.001 at 7.15 and 16.425 GHz were found. Figure  5b is the plot of the tunability versus the frequency of the multilayer, showing that a large dielectric tunability of 12% to 35% has been achieved from 5 to 18 GHz with a bias voltage of 200 V or an applied field of 200 kV/cm. These results indicate that the optimized dielectric performance for such #selleck inhibitor randurls[1|1|,|CHEM1|]# a designed multilayer occurs at 10 to 12 GHz check details with an optimized dielectric constant of 445, a dielectric loss of 0.01, and a dielectric tenability of 35%. Overall, the microwave dielectric property of the BTO/STO multilayer on (001) MgO suggests that this system can be developed for room-temperature tunable microwave elements and related device applications. Figure 5 Plots of (a) relative dielectric constant and loss tangent and (b) tunability of BTO/STO superlattices. Conclusions In summary, ferroelectric BTO/STO multilayers have been epitaxially grown

on (001) MgO by pulsed laser deposition. The microstructural studies from X-ray diffraction show that the as-designed multilayers are c-axis oriented with good epitaxial nature. The high-frequency microwave (5 to 18 GHz) dielectric measurements reveal that the multilayers have excellent microwave dielectric properties with very low dielectric loss and high dielectric tenability, which suggests Tolmetin that the BTO/STO multilayers on (001) MgO have great potential for the development of room-temperature tunable microwave

elements and related applications. Acknowledgements This research was partially supported by the National Science Foundation under NSF-NIRT-0709293 and the Natural Science Foundation of China under 11028409. Also, Dr. Ming Liu and Dr. Chunrui Ma would like to acknowledge the support from the ‘China Scholarship Council’ for their PhD researches at UTSA. References 1. Tagantsev AK, Sherman VO, Astafiev KF, Venkatesh J, Setter N: Ferroelectric materials for microwave tunable applications. J Electroceramics 2003, 11:5–66.CrossRef 2. Lin Y, Chen CL: Interface effects on highly epitaxial ferroelectric thin films. J Mat Sci 2009, 44:5274–5287.CrossRef 3. Chen CL, Shen J, Chen SY, Luo GP, Chu CW, Miranda FA, Van Keuls FW, Jiang JC, Meletis EI, Chang H: Epitaxial growth of dielectric Ba 0.6 Sr 0.4 TiO 3 thin film on MgO for room temperature microwave phase shifters. Appl Phys Lett 2001, 78:652–654.CrossRef 4. Sriram S, Bhaskaran M, Mitchell DG, Mitchell A: Lattice guiding for low temperature crystallization of rhombohedral perovskite-structured oxide thin films.