Studies of ferroelectric PMN-PT

by Jace Harker


Piezoelectrics are all around us!

The quartz crystal counting seconds in your watch is a piezoelectric crystal.

A piezoelectric motor might be focusing the miniature camera in your cell phone.

Every day, doctors use ultrasound to check that an unborn child is healthy inside the mother... is it a boy or a girl? Piezoelectrics make the ultrasonic sounds that make it possible. Doctors use the same ultrasound to check a beating heart for problems without making a single cut in the patient.

Do you enjoy fishing? Sonar fish finders use piezoelectrics to tell where the fish are. In deeper water, sonar allows ships and submarines to find underwater rocks, mountains, wrecks, or other submarines.

From the very small to the very large, scientists and engineers use scanning tunneling microscopes and large optical telescopes to study individual atoms and far-away galaxies, and piezoelectrics make them all possible!

My project involves studying some of the features of a particular kind of piezoelectric called PMN-PT. The project is broken down into several sections for your viewing pleasure:

    1. Introduction - A basic overview of some of the concepts important in this work. This section was written to be more accessible to the general reader, while the later sections assume more technical knowledge.
    2. X-ray Mapping - Using X-ray analysis to look for ferroelectric domains.
    3. TEM Electron Diffraction - Studying the phases of PMN-PT using electron diffraction.
    4. SEM Domain Hunting - Looking for ferroelectric domains using a combination of SEM, mechanical etching, and DIC optical microscopy!



I would most sincerely like to thank Brian McIntyre, who provided more help, advice, interest, care, and patience than I had any right to expect.

Much credit should go to Steve Robinson, our lab technician and crystal wizard, who cuts and polishes our crystal samples and who also performed the final mechanical relief polish on the SEM sample.

Scott Russell from the Mech.E. department found exactly the power supply I was looking for, after I'd given up all hope.

Thanks to my advisor, Prof. David Quesnel, whose microscope and lab equipment I used to take pictures and mount samples. Also, this work was supported by ONR code 332, Dr. A. K. Vasudevan, Scientific Officer. Collaboration with Dr. Lynn Ewart (NUWC Newport) and Dr. Pengdi Han (HC Materials) is gratefully acknowledged.

Finally, many thanks to my girlfriend Yasmin, who was amazingly patient with my eccentricities, and who brought dinner to the lab for me once or twice at ridiculously late hours.


You comments, questions, critiques, etc. are greatly appreciated!

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