Title page for etd-0529114-214141


[Back to Results | New Search]

URN etd-0529114-214141
Author Bo-Lin Lee
Author's Email Address No Public.
Statistics This thesis had been viewed 5580 times. Download 747 times.
Department Physics
Year 2013
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Magnetic and dielectric study on spin-frustrated ZnV2O4
Date of Defense 2014-05-31
Page Count 79
Keyword
  • spinel structure
  • multiferroics
  • structural transition
  • spin glass
  • spin frustrated
  • impedance
  • Abstract The purpose of this work is to study the correlation of magnetic and dielectric property in the spin-frustrated ZnV2O4 spinel oxide. The geometrically frustrated spinel ZnV2O4 prepared using solid state reaction method followed by annealing at different temperatures. X-ray diffraction (XRD) has been employed to check the phase purity of the sample. From XRD analysis, we found that, with increase of sintering temperature from 800℃ to 900℃ the secondary phases in appeared in XRD spectrum. Riveted analysis using GSAS software has been employed for structural refinement. The refinement fit to cubic crystal structure with Fd-3m space group with lattice parameter a = 8.31Å. Magnetization measurements reveal multiple magnetic transitions corresponding to cubic to tetragonal structural transition (52 K) and spin-glass-like behavior (9 K) respectively.
      Among the dielectric measurement, huge permittivity with huge frequency dispersion has been noticed. With decreasing temperature, dielectric permittivity exhibit step like drop and this drop shift to high temperature for higher frequencies. And we did not find ferroelectric signature in dielectric spectrum. Therefore, we initially exclude the possibility of multiferroics of ZnV2O4. Moreover, frequency-impedance diagrams and modulus spectrum reveal the electrical heterogeneity across the grain and grain boundary. Based on our results, we attributed the huge dielectric constant to Maxwell - Wagner interfacial polarization.
    Advisory Committee
  • Yung-Sung Chen - chair
  • Jim-Long Her - co-chair
  • Chin-Shan Lue - co-chair
  • Hung-Duen Yang - advisor
  • Files
  • etd-0529114-214141.pdf
  • Indicate in-campus at 0 year and off-campus access at 1 year.
    Date of Submission 2014-06-29

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have more questions or technical problems, please contact eThesys