skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Stress Induced Monoclinic Phase in Epitaxial BaTiO3 on MgO

Abstract

We present a detailed strain analysis of epitaxial ferroelectric films taking into account multiple sources of strain, including the lattice mismatch between the film and the substrate, thermal strains due to differences in the thermal expansion coefficients of the film and the substrate, and relaxation by the formation of interfacial dislocations. The lattice parameters of the film are calculated using a thermodynamic formalism coupled with the strain analysis. The theoretical model shows that epitaxial (001) BaTiO{sub 3} films on (001) MgO are expected to display successive phase transformations with decreasing temperatures that are different than the bulk. This is verified experimentally for 50 nm thick (001) BaTiO{sub 3} films grown on (001) MgO substrates at 720 C using pulsed laser deposition. A synchrotron x-ray diffraction study displays two slope changes in the temperature dependence of the out-of-plane lattice constant. This indicates that two phase transformations exist in the film as a function of temperature with transition temperatures and lattice constants that are consistent with the theoretically predicted phases. Theoretical results show that the first transformation at around 270 C corresponds to a paraelectric-ferroelectric transition. The ferroelectric phase has an orthogonal symmetry (Amm2) with in-plane polarization components. The transformation at aroundmore » -20 C is an Amm2<-->Pm transition between two ferroelectric phases. The ferroelectric Pm phase is monoclinic compared to the rhombohedral R3m phase in bulk.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914236
Report Number(s):
BNL-78804-2007-JA
Journal ID: ISSN 0021-8979; JAPIAU; TRN: US200809%%5
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Appl. Phys.; Journal Volume: 99
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BARIUM OXIDES; TITANIUM OXIDES; SUBSTRATES; MAGNESIUM OXIDES; STRESS ANALYSIS; LATTICE PARAMETERS; PHASE TRANSFORMATIONS; TEMPERATURE DEPENDENCE; THERMAL EXPANSION; EPITAXY; FERROELECTRIC MATERIALS; national synchrotron light source

Citation Formats

Misirlioglu,I., Alpay, S., He, F., and Wells, B. Stress Induced Monoclinic Phase in Epitaxial BaTiO3 on MgO. United States: N. p., 2006. Web. doi:10.1063/1.2198938.
Misirlioglu,I., Alpay, S., He, F., & Wells, B. Stress Induced Monoclinic Phase in Epitaxial BaTiO3 on MgO. United States. doi:10.1063/1.2198938.
Misirlioglu,I., Alpay, S., He, F., and Wells, B. Sun . "Stress Induced Monoclinic Phase in Epitaxial BaTiO3 on MgO". United States. doi:10.1063/1.2198938.
@article{osti_914236,
title = {Stress Induced Monoclinic Phase in Epitaxial BaTiO3 on MgO},
author = {Misirlioglu,I. and Alpay, S. and He, F. and Wells, B.},
abstractNote = {We present a detailed strain analysis of epitaxial ferroelectric films taking into account multiple sources of strain, including the lattice mismatch between the film and the substrate, thermal strains due to differences in the thermal expansion coefficients of the film and the substrate, and relaxation by the formation of interfacial dislocations. The lattice parameters of the film are calculated using a thermodynamic formalism coupled with the strain analysis. The theoretical model shows that epitaxial (001) BaTiO{sub 3} films on (001) MgO are expected to display successive phase transformations with decreasing temperatures that are different than the bulk. This is verified experimentally for 50 nm thick (001) BaTiO{sub 3} films grown on (001) MgO substrates at 720 C using pulsed laser deposition. A synchrotron x-ray diffraction study displays two slope changes in the temperature dependence of the out-of-plane lattice constant. This indicates that two phase transformations exist in the film as a function of temperature with transition temperatures and lattice constants that are consistent with the theoretically predicted phases. Theoretical results show that the first transformation at around 270 C corresponds to a paraelectric-ferroelectric transition. The ferroelectric phase has an orthogonal symmetry (Amm2) with in-plane polarization components. The transformation at around -20 C is an Amm2<-->Pm transition between two ferroelectric phases. The ferroelectric Pm phase is monoclinic compared to the rhombohedral R3m phase in bulk.},
doi = {10.1063/1.2198938},
journal = {J. Appl. Phys.},
number = ,
volume = 99,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}