Dissertation > Excellent graduate degree dissertation topics show

Microstructure and Electrocaloric Effect of Oriented PLZST Thin Films

Author: YeMao
Tutor: ChenXiangQun
School: Harbin Institute of Technology
Course: Materials Physics and Chemistry
Keywords: PLZST thin films Orientation Microstructrue Electrocaloric effect
CLC: TB383.2
Type: Master's thesis
Year: 2009
Downloads: 64
Quote: 0
Read: Download Dissertation

Abstract


The electrocaloric effect（ECE） is a change in the temperature of a material upon the application or withdrawal of an electric field under adiabatic conditions. The ECE could have a unique advantage to provide cooling solutions for small systems and small refrigeration load occasions （MEMS system） ,as for their mading simple with no mechanical moving parts, controlling of flexible, high-energy conversion rate, low cost, environmentally friendly compared with traditional cooling.In this paper, highly oriented Pb0.97La0.02Zr0.82Sn0.15Ti0.03O3（PLZST） antiferroelectric thin films were prepared on the Pt, PbO, LaNiO3（LNO） substrates and PLZST / Pt / PLZST, PLZST / LNO / PLZST layer-by-layer structures were prepared by the sol - gel method and rapid thermal processing technology（RTA）. Microstructure of PLZST thin films was systematically investigated by scanning electron microcopy（SEM）, X-ray diffractometer（XRD） and other means, and mechanism for the growth of oriented PLZST thin films were discussed. The orientation of PLZST thin films were controlled by the intermediate phase or seed layer. When the transient compound was well epitaxial with Pt（111）, the （111）-oriented PLZST films can be obtained by RTA process, in which PLZST thin films grow on the transient compound as a seeding layer. The transition compounds provides a good lattice–matching with PLZST（100）, the （100）-oriented PLZST thin films can be obtained. SEM analysis showed that the different oriented thin films have different surface morphology.The ferroelectric and dielectric properties of different oriented PLZST thin films were systematically studied. PLZST films have double hysteesis loop under the applied electric field, which show a good antiferroelectric properties. The testing of the hysteresis loops at various temperatures for PLZST thin films showed that antiferroelectric（AFE） - ferroelectric（FE） - paraelectric（PE） phase transition appear with the rise of temperature. Then, on cooling to minimize, followed by the occurrence paraelectric（PE）-ferroelectric（FE）-antiferroelectric（AFE） phase transition. The test results of temperature dependence of the dielectric constant of PLZST thin films shows that the Curie temperature of PLZST thin films moved to lower temperature than the Zr-rich PZT. antiferroelectric phase can be broaden and stabilized and the Curie temperature of Zr-rich PZT could be reduced by substituting with La3+and Sn4+.The ECE of oriented PLZST thin films were evaluated. Analysis results showed that electrocaloric temperature change of PLZST film increases with temperature increase up to Curie temperature and then decreases. The maximal EC temperature change appears near the Curie temperature. The electrocaloric temperature change of （111）-oriented PLZST films excelled that of （100）-oriented film. Finally, the ECE of layer-by-layer structure of PLZST films were analyzed, and the promoising applications of ECE of layer-by-layer structure in the fluorine-free refrigerator and refrigeration systems for MEMS were discussed.

Related Dissertations

  1. Preparation and Electrocaloric Effect of BaxSr1-xTiO3 Ferroelectric Thin Films,TB383.2
  2. Grid-Side Converter Control and Wind Turbine Emulator in Direct Drive Wind Power System,TM46
  3. Marketing Strategy of China campus buy,F274
  4. Underground Locomotive Design of the Regional Location Detection System,TD524.3
  5. Interaction Analysis Perspective Students interpersonal factors and Promotion Strategies,G645.5
  6. A Research on the Improvement of Legal System Concerning Labor Dispatching in China,D922.5
  7. Research of Preparation of BT and NBT Oriented Piezoelectric Ceramics in a Magnetic Field,TM282
  8. The Precise Positioning System of the Electric Locomotive Underground Coal Mine Based on Strap-down Inertial Navigation,TN966
  9. Research of Speed Sensorless Vector Control System Based on Stator Flux-oriented,TP212
  10. Optimization of New Production Development Process in Industrial Adhesive Business of HG Company,F273
  11. Phosphorus zinc germanium infrared crystal growth and properties of,O782
  12. The Finite Element Simulation on Plastic Behavior of Pure Titanium,TG146.23
  13. Discussion n Major Issues and Solution Advice in Administrative Reconsideration System in China,D922.1
  14. A Study on the Value Orientation of Mass Media in Crisis Communication,G206
  15. An Intercultural Study of Chinese and Western Personality,C912.4
  16. The Puzzlement and Surpass of Character Location,G471.2
  17. Analysis of Female Graduates’ Employment Orientation and Its Reasons,G647.38
  18. Research on the Orientation of Ideological and Political Education in the Vision of Cultural Soft Strength,G641
  19. Strategic management concept local colleges Orientation Issues,G648.4
  20. Orientation of Cultivation Target of Social Sports Specialty and Social Demand Adaptability Research in the Xinjiang Colleges and Universities,G807.4
  21. Junior Tennis Players Achievement goals and the relationship between life satisfaction,G845

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net  Mobile