Subcategory: Materials Science
Amrit Sharma - Norfolk State University
Co-Author(s): Dhiren K. Pradhan, Geophysical Laboratory, Washington D.C.; Bo Xiao, Norfolk State University, Norfolk, VA; Sangram K. Pradhan, Norfolk State University, Norfolk, VA; Messaoud J. Bahoura, Norfolk State University, Norfolk, VA
Recently ferroelectric nanostructures have attracted attention to the scientific community owing to fundamental scientific interest, especially for energy-harvesting devices, advanced sensors, and nonvolatile random access memory applications. Relaxor ferroelectric provides a high electric displacement or charge density, a large area to store the energy and fast discharge capacity. Lead-free barium calcium titanate (BCT)/barium zirconium titanate (BZT) multilayer heterostructures were grown epitaxially by pulsed laser deposition (PLD) with an excimer laser (KrF, 248 nm). The thin film heterostructures were deposited at 800°C under an oxygen pressure of 20 mTorr, with a laser energy density of ~2.5 J/cm2 and a pulse rate of 5 Hz. X-ray diffraction θ-2θ scans showed highly oriented (l00) diffraction peaks from the substrate and pseudo-cubic reflections from the material confirms epitaxial nature of these films. The atomic force microscopy (AFM) studies revealed that the surfaces of all the thin films are observed to be smooth and homogeneous, free of micro-cracks, pores or holes with average surface roughness around 1 nm. These thin films exhibit remanent and saturation polarization up to 64 μC/cm2 and 137 μC/cm2 respectively. Temperature dependence of dielectric and ferroelectric hysteresis behavior have also been studied. The heterostructures show saturated large polarization, low loss tangent, good recoverable energy storage densities, and energy storage efficiencies well above the room temperature which may be useful for nanoscale multifunctional device applications.Not Submitted
Funder Acknowledgement(s): This work is supported by the NSF-CREST Grant number HRD 1547771 and NSF-CREST Grant number HRD 1036494.
Faculty Advisor: Messaoud J. Bahoura, firstname.lastname@example.org
Role: Synthesis, fabrication, characterization, and utilization of lead-free barium calcium titanate (BCT)/barium zirconium titanate (BZT) multilayer heterostructures for high energy density capacitor applications.