Ba0.5Sr0.5TiO3/Bi1.5Zn1.0Nb1.5O7　(BST/BZN)　multilayer　thin.　films　were　prepared　on　Pt/Al2O3　substrates　by　sol-gel　method.　The　structure,　morphology,　and　tunable　dielectric　properties　of　BST/BZN　thin.　films　were　investigated.　X-ray　diffraction　results　showed　that　the　structure　of　BST/BZN　multilayer　thin.　films　was　composed　of　a　cubic　BZN　pyrochlore　phase　and　a　cubic　BST　perovskite　phase.　The　diffraction　pattern　confirmed　that　there　was　no　measurable　reaction　occurred　between　the　BST　and　BZN　layers.　The.　field-emission　scanning　electron　microscope　(FESEM)　showed　that　the　surface　of　BST/BZN　multilayer　thin.　films　was　crack-free　and　compact.　The　dielectric　constant　and　loss　tangent　of　the　BST/BZN　multilayer　thin.　films　were　106　and　0.011　at　10　kHz,　respectively.　The　dielectric　tunability　was　10%　under　dc　bias.　field　of　355　kV/cm　at　10　kHz.　The　medium　dielectric　constant,　low　loss　tangent　and　tunability　of　the　dielectric　constant　suggest　that　BST/BZN　multilayer　thin.　films　have　potential　application　for　tunable　microwave　device　applications.　(C)　2008　Elsevier　B.　V.　All　rights　reserved.