Presentation Title

Investigation of low temperature ferroelectric phase transitions in nonlinear compounds

Faculty Mentor

Dr. Tim Usher

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 37

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Ferroelectric compounds exhibit spontaneous polarization below the ferroelectric Curie temperature. Spontaneous polarization in ferroelectrics has two or more polar electric states and may be switched from one state to the other by an external electric field. The identification of this phase transition or Curie points indicates the possibility that a material is ferroelectric, having a remnant polarization. Phase transitions occur at a specific temperature and indicates that the dipoles in the axis of polarization are aligned. The study for ferroelectric materials is important because they may be used as capacitors, piezo-actuators, as well as providing engineering and medical applications. We determined the Curie points for two known ferroelectrics. Potassium Dihydrogen Phosphate (KDP) was 122 K anddeuterated Potassium Dihydrogen Phosphate (DKDP) was 222 K. This is consistent with other published reports. Newly proposed ferroelectric candidates were also tested. Preliminary results indicate a phase transition in Bis(Diisopropylamonium) Cobalt(II) Tetrachloridebetween the range of 228 K and 248K. Results obtained for Melamine Hemihydrate Hydrochloride are inconclusive to claim a Curie temperature. To investigate this phenomenon, a cryogenic experimental system was developed that measures capacitive reactance as a function of temperature. The cryogenic system is a liquid nitrogen cold finger that can operate between 77 K and room temperate. The examination of capacitance versus temperature will allow for further study of potential ferroelectric and piezoelectric molecules, specifically, observing nonlinear elements in the analysis.

This research was supported by the National Science Foundation under the CREST program (NSF-HRD #1345163)

Ferroelectric, Phase Transitions, Cryogenic, Polarization, Capacitive Reactance, Piezoelectric, Nonlinear

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Investigation of low temperature ferroelectric phase transitions in nonlinear compounds

CREVELING 37

Ferroelectric compounds exhibit spontaneous polarization below the ferroelectric Curie temperature. Spontaneous polarization in ferroelectrics has two or more polar electric states and may be switched from one state to the other by an external electric field. The identification of this phase transition or Curie points indicates the possibility that a material is ferroelectric, having a remnant polarization. Phase transitions occur at a specific temperature and indicates that the dipoles in the axis of polarization are aligned. The study for ferroelectric materials is important because they may be used as capacitors, piezo-actuators, as well as providing engineering and medical applications. We determined the Curie points for two known ferroelectrics. Potassium Dihydrogen Phosphate (KDP) was 122 K anddeuterated Potassium Dihydrogen Phosphate (DKDP) was 222 K. This is consistent with other published reports. Newly proposed ferroelectric candidates were also tested. Preliminary results indicate a phase transition in Bis(Diisopropylamonium) Cobalt(II) Tetrachloridebetween the range of 228 K and 248K. Results obtained for Melamine Hemihydrate Hydrochloride are inconclusive to claim a Curie temperature. To investigate this phenomenon, a cryogenic experimental system was developed that measures capacitive reactance as a function of temperature. The cryogenic system is a liquid nitrogen cold finger that can operate between 77 K and room temperate. The examination of capacitance versus temperature will allow for further study of potential ferroelectric and piezoelectric molecules, specifically, observing nonlinear elements in the analysis.

This research was supported by the National Science Foundation under the CREST program (NSF-HRD #1345163)

Ferroelectric, Phase Transitions, Cryogenic, Polarization, Capacitive Reactance, Piezoelectric, Nonlinear