AVS 50th International Symposium
    Electronic Materials and Devices Wednesday Sessions
       Session EM-WeM

Paper EM-WeM8
Dielectric Response of Asymmetric KNbO@sub 3@/KTaO@sub 3@ Superlattices

Wednesday, November 5, 2003, 10:40 am, Room 321/322

Session: Multifunctional Electronic Materials
Presenter: J. Sigman, University of Florida
Authors: J. Sigman, University of Florida
H.J. Bae, University of Florida
D.P. Norton, University of Florida
J.D. Budai, Oak Ridge National Laboratory
P.H. Fleming, Oak Ridge National Laboratory
L.A. Boatner, Oak Ridge National Laboratory
Correspondent: Click to Email
The K(Ta,Nb)O@sub 3@ perovskite is an interesting paraelectric/ferroelectric system with tunability of the dielectric response with applied electric field. Pulsed laser deposition (PLD) has been used to achieve atomic layer-by-layer growth in KTaO@sub 3@/KNbO@sub 3@ superlattices. Previously, a symmetric 1 unit cell x 1 unit cell KTaO@sub 3@/KNbO@sub 3@ was grown on KTaO@sub 3@(100) and its dielectric response and structural properties were studied. Increasing capacitance with increasing applied dc bias for temperatures just below the structural transition was observed and suggested an anitiferroelectric response. We have investigated several asymmetric KTaO@sub 3@/KNbO@sub 3@ superlattices to provide further elucidation on this anomalous dielectric response. This positive tunability appears to be a function on the thickness the KNbO@sub 3@ layer. Above three unit cells of KNbO@sub 3@, the positive tunability disappears. Below three unit cells of KNbO@sub 3@, the positive tunability is seen in the same temperature region as the 1 x 1 superlattice, regardless of the Nb:Ta thickness ratio.