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Title: Polarization switching characteristics of 0.5BaTi{sub 0.8}Zr{sub 0.2}O{sub 3}-0.5Ba{sub 0.7}Ca{sub 0.3}TiO{sub 3} lead free ferroelectric thin films by pulsed laser deposition

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.4871673· OSTI ID:22273569
 [1]; ;  [2];  [3]
  1. Department of Physics, Astronomy and Materials Science, Missouri State University, Springfield, Missouri 65897 (United States)
  2. National Chemical Laboratory (CSIR-NCL), Council of Scientific and Industrial Research, Dr. Homi Bhabha Road, Pashan, Pune 411 008, Maharashtra (India)
  3. Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

We report on the ferroelectricity for morphotropic-phase-boundary lead (Pb) free 0.5BaTi{sub 0.8}Zr{sub 0.2}O{sub 3}-0.5Ba{sub 0.7}Ca{sub 0.3}TiO{sub 3} (0.5BZT-0.5BCT) thin films. Thin films were grown on Pt/Ti/SiO{sub 2}/Si substrate using pulsed laser deposition. Raman spectroscopic data combined with the X-ray diffraction analyses confirm body centered tetragonal crystallographic structure 0.5BZT-0.5 BCT thin films on Pt/Ti/SiO{sub 2}/Si. Polarization studies demonstrate that these 0.5BZT-0.5BCT films exhibit a large remnant and saturation polarization of 37 μC/cm{sup 2} and 40 μC/cm{sup 2}, respectively, with a coercive field of 140 kV/cm. A correlation between polarization dynamics, structural distortion, and phonon vibration is established. The splitting of X-ray diffraction peak of the thin film in the 2θ range of 44.5° to 46.5° represents high degree of tetragonality. The tetragonality factor calculated by Rietveld analysis was found to be 0.006 and can be a major cause for the increased remnant polarization value. It is established from Raman spectra that the non-centrosymmetricity due to the displacement of Ti/Zr ions from its octahedral position is related to the peak position as well as the broadening of the A{sub 1} (LO) optical phonon mode. This increase of broadness in the thin film causes an increase in the dipole moment of the unit cell and, hence, the net increase in polarization values.

OSTI ID:
22273569
Journal Information:
Journal of Applied Physics, Vol. 115, Issue 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
Country of Publication:
United States
Language:
English