Browsing by Author "Luo, Nengneng"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Enhanced energy storage performance of (1-x)(BCT-BMT)-xBFO lead-free relaxor ferroelectric ceramics in a broad temperature range
    (Elsevier, 2019-03-03) Xu, Mengxing; Peng, Biaolin; Zhu, Jinian; Liu, Laijun; Sun, Wenhong; Leighton, Glenn J. T.; Shaw, Christopher; Luo, Nengneng; Zhang, Qi
    Relaxor ferroelectrics with high energy storage performances are very attractive for modern applications in electronic devices and systems. Here, it is demonstrated that large energy densities (0.52e0.58 J/cm3) simultaneously with high efficiencies (76è2%) and thermal stabilities (the minimum variation of efficiency < 4% from 323 K to 423 K at x ¼ 0.04) have been achieved in the (1-x)(BCT-BMT)-xBFO lead-free relaxor ferroelectric ceramics prepared using a conventional solid-state reaction method. Large dielectric breakdown strengths and great relaxor dispersion around the dielectric peaks are responsible for the excellent energy storage performances. The energy storage performances of as-prepared ceramics at high BFO doping amount (x ¼ 0.06 and 0.07) were deteriorated seriously due to low dielectric breakdown strengths. However, they could be greatly improved when aged, since the operable electric field was significantly enhanced from 10 kV/cm of as-prepared samples to 100 kV/cm of aged samples due to the reduced concentration of oxygen vacancies during the aging process. The excellent energy storage performances may make them attractive materials for applications in modern energy storage systems in a broad temperature range.
  • Thumbnail Image
    ItemOpen Access
    Tailoring the electrocaloric effect of Pb0.78Ba0.2La0.02ZrO3 relaxor thin film by GaN substrates
    (Royal Society of Chemistry, 2019-11-06) Peng, Biaolin; Jiang, Jintao; Tang, Silin; Zhang, Miaomiao; Liu, Laijun; Zou, Bingsuo; Leighton, Glenn J. T.; Shaw, Christopher; Luo, Nengneng; Zhang, Qi; Sun, Wenhong
    The electrocaloric (EC) effect in ferroelectric/antiferroelectric thin films has been widely investigated due to its potential applications in solid state cooling devices. It is demonstrated that the EC effect of the Pb0.78Ba0.2La0.02ZrO3 (PBLZ) relaxor thin films prepared by using a sol–gel method strongly depends on the substrates. The maximum ΔT of PBLZ thin films deposited on Pt(111)/TiOx/SiO2/Si(100) (Pt), LaNiO3/Pt(111)/TiOx/SiO2/Si(100) (LaNiO3/Pt), LaNiO3/n-type GaN (LaNiO3/n-GaN) and LaNiO3/p-type GaN (LaNiO3/p-GaN) substrates is ∼13.08 K, 16.46 K, 18.70 K, and 14.64 K, respectively. Moreover, negative EC effects in a broad temperature range (∼340 K to 440 K) could be obtained in the thin films deposited on LaNiO3/n-GaN and LaNiO3/p-GaN substrates, which is ascribed to higher proportions of orthorhombic antiferroelectric phase to rhombohedral ferroelectric phase induced by the GaN substrates. These results indicate that tailoring the EC effects by changing the substrates could provide a new strategy in designing an EC cooling device with high cooling efficiency.