The preferentially (100)-oriented (Ba0.75Sr0.25)(Zr0.25Ti0.75)O-3 (BSZT) thin films were deposited on Pt(111)/Ti/SiO2/ Si(I 0 0) substrates by a pulsed laser deposition process. The films exhibited columnar-grained characteristics with grain sizes of 30-80 nm. The temperature dependence of dielectric constants was investigated; it is shown that the cubic to rhombohedral phase transition temperature is located at the vicinity of 200 K. At 300 K and 1 MHz, the dielectric constant and loss tan 6 are 321 and 0.014, respectively. The dielectric constant of BSZT film changes significantly with applied DC bias field and has a high tunability of similar to 53% at 1 MHz and an applied field of 600kV/cm. (c) 2004 Elsevier B.V. All rights reserved.