(Ba0.50Sr0.50)TiO3 (BST) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates without and with LaNiO3 (LNO) bufferlayer prepared by pulsed laser deposition (PLD). The BST thin films directly grown on Pt/Ti/SiO2/Si substrates without and with LNO bufferlayer exhibited highly (100) and (I 10) orientation, respectively. The dielectric constant of the 800-nm-thick BST films with LNO bufferlayer was 1010 at 1 MHz, which was higher than that of BST film with non-bufferlayer (similar to 851). Also, the tunabilities of BST thin films with (100)- and (110)-orientation were similar to 63% and similar to 62%, respectively, at the applied field of 262.5 kV/cm. Improved dielectric constant has been attributed to LNO bufferlayer. (c) 2005 Elsevier B.V. All rights reserved.