Doctoral Dissertations

Abstract

This study investigates the dielectric properties of single crystal and ceramic strontium titanate (SrTiO3) for cryogenic capacitor applications from room temperature to 4 K. Permittivity (k) and loss tangent are dependent on temperature, frequency, mechanical stress, and applied DC electric field. Accordingly, the dielectric constant and loss tangent were measured at various frequencies and DC bias levels. Loss tangent data are also presented as equivalent series resistance (ESR). For single crystal SrTiO3, an impurity level of ≈500 ppm barium resulted in an increase of the maximum permittivity to approximately 50,000 at 6 K. This relatively high permittivity value was tunable by up to 80% at a low DC field of less than 1 kV/cm between 4 K and 80 K. For ceramic SrTiO3, field-dependent permittivity data are used to calculate the energy density up to the dielectric breakdown voltage. The results demonstrate that cryogenic operation can enhance energy storage through increased permittivity and improved dielectric strength at cryogenic temperatures. The breakdown field increased from approximately 440 kV/cm at 295 K to 770 kV/cm at 77 K, while the corresponding energy density rose from 2.1 J/cm³ to 4.9 J/cm³, respectively. Possible mechanisms for the increase in breakdown voltage with decreasing temperatures are discussed. This study provides a framework for evaluating SrTiO3-based multilayer ceramic capacitors in the context of cryogenic applications with emphasis on energy storage.

Advisor(s)

Dogan, Fatih

Committee Member(s)

Brow, Richard K.
Huebner, Wayne
O'Malley, Ronald J.
Gu, Yijia
Burn, Ian

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2026

Journal article titles appearing in thesis/dissertation

Paper I, found on pages 34-57, has been published in the Journal of Materials Science: Materials in Electronics.

Paper II, found on pages 58-80, has been published in the Journal of Materials Science: Materials in Electronics.

Paper III, found on pages 81-103, has been published in the Journal of Electroceramics.

Pagination

xiii, 137 pages

Note about bibliography

Includes_bibliographical_references_(pages 131-136)

Rights

© 2026 Hung Trinh , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12610

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