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Advanced Physics Laboratories

       
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Ferroelectric Phase Transitions

ABOUT THE EXPERIMENT

“Ferroelectric” materials are the electrical analogy of ferromagnets: below a certain temperature, they can carry a permanent electric dipole moment. In this experiment, you will measure the polarization and capacitance of a ferroelectric crystal (TGS) as a function of temperature, and see the onset of "spontaneous polarization" at the transition temperature of about 50 deg C. The results are analyzed in comparison to ferromagnetism, and in terms of the Landau theory, to infer some of the universal characteristics of second order phase transitions

WHAT YOU WILL LEARN
  • The Curie paramagnet. Ferromagnetism: magnetization and susceptibility at the Curie point.
  • Principles of ferroelectrics
  • The theory of second order phase transitions and critical phenomena
  • Use of thermocouple, precision electrometer, Keithly LCZ meter.
PREPARATION
  • Required reading:
    • L.Landau, Statistical Physics, Chapter on "Phase Transitions of the Second Kind"
    • H. P. Meyers, Introductory Solid State Physics, Chap. 11, Sections 11.1-11.5, and also Appendix 11.4.
    • "Ferro-Electric Phase Transitions and Critical Phenomena" 441-442 Laboratory Procedure (PDF)
  • Recommended reading: 
    • H. E.Stanley, Introduction to Phase Transitions and Critical Phenomena, Chap 1,2,6.
OTHER DOCUMENTATION
  • Under construction