부산대학교 도서관

Oriented (Ba$_{0.6}$,Sr$_{0.4}$)TiO$_3$ (BST60) and graded (Ba,Sr)TiO$_3$ (BST) films were deposited on MgO (001) single crystals by using a pulsed laser deposition method. Structural properties of the films were investigated by using an X-ray diffractometer. The dielectric properties of the films were investigated under a dc bias field of 0 $-$ 20 V in the temperature region from 173 to 393 K by using interdigital capacitors (IDC) fabricated by photolithography and an etching process. The temperature-dependent small-signal dielectric properties of the films were measured with a Keithley 590 C-V meter. The measured temperature-dependent tunability for an IDC device based on BST60/MgO, BT/$\cdot\cdot$/ST/MgO and ST/$\cdot\cdot$/BT/MgO multilayer structure showed interesting data. The trends of the dielectric properties of the IDC may be due to the fact that they are affected by Curie temperature, lattice constant, strain/stress, {\it etc.}