Document Type
Article
Original Publication Date
2010
Journal/Book/Conference Title
Journal of Applied Physics
Volume
107
Issue
8
DOI of Original Publication
10.1063/1.3359707
Date of Submission
October 2015
Abstract
Dielectric properties of annealed and as-grown ferroelectricBa0.5Sr0.5TiO3 (BST) grown by pulsed laser deposition on sputtered BST seed layers on strontium titanate (STO) substrates were investigated at microwave frequencies in the realm of tunability of its dielectric constant as well as phase shifters based on this material. The as-grown layers were nearly fully relaxed with measured lattice parameters nearly identical to those of bulk BST. The tuning of the relative dielectric constant (∼1750 at zero bias at 10 GHz) of the annealed BST was found to be as high as 59% and 56% at 10 and 19 GHz, respectively. The analysis of the loss in the BST results in a measured tan δ of 0.02 for the annealed as well as the unannealed films at a frequency of 18 GHz. Phase shifters also exhibited high tuning with differential phase shift figures of merit of 35 and 55°/dB at a field of 60 kV/cm at 10 and 19 GHz, respectively. Serendipitously, most of the tuning occurs at low fields, and thus we propose a new figure of merit, taking into account the amplitude of applied electric field in order to achieve the phase shift. In this new realm we achieved the values of this overall figure of merit of 1.2 and 1.8° cm/dB kV at 10 and 19 GHz, respectively, using an applied electric field of only 10 kV/cm.
Rights
Leach, J. H., Liu, H., & Avrutin, V., et al. Large dielectric tuning and microwave phase shift at low electric field in epitaxial Ba0.5Sr0.5TiO3 on SrTiO3. Journal of Applied Physics, 107, 084511 (2010). Copyright © 2010 American Institute of Physics.
Is Part Of
VCU Electrical and Computer Engineering Publications
Comments
Originally published at http://dx.doi.org/10.1063/1.3359707