Crystallographic and dielectric properties of highly oriented BaTiO3 films

Influence of oxygen pressure utilized during pulsed laser deposition

Jussi Hiltunen (Corresponding Author), D. Seneviratne, H.L. Tuller, J. Lappalainen, V. Lantto

Research output: Contribution to journalArticleScientificpeer-review

26 Citations (Scopus)

Abstract

The crystal structure of BaTiO3 thin films grown by pulsed laser deposition on MgO substrates was found to be strongly influenced by the oxygen pressure used during growth. Low pressures produced epitaxial films with highly strained out-of-plane lattice parameter c compared to in-plane parameter a, while increasing oxygen pressure resulted in the ratio c/a < 1 with a concomitant increase in polycrystallinity. The dielectric properties varied with changing crystal structure reaching a maximum permittivity value in films near the minimum point of tetragonal distortion and exhibiting relaxor-like behavior in c/a < 1 films close to this point. Hysteresis observed in dielectric tuning loops pointed to the presence of the ferroelectric phase in all films at room temperature. As a result of high electric field poling treatment at 300 °C, the tunability generally increased and initially symmetric tuning curves became asymmetric. The tuning curve in c/a < 1 samples became nearly linear, supporting the premise of polarization reorientation with changing deposition condition. Phase transitions to the paraelectric phase were highly suppressed and shifted upwards in temperature from the bulk transition temperature of 130 to ∼250 °C in strongly c-oriented films. Moderate shifts in oxygen working pressure were demonstrated to produce films with very different properties thereby offering convenient means for strain engineering and control of preferred crystal orientation and polarization direction of highly oriented BTO films.
Original languageEnglish
Pages (from-to)395-404
Number of pages10
JournalJournal of Electroceramics
Volume22
Issue number4
DOIs
Publication statusPublished - 2009
MoE publication typeA1 Journal article-refereed

Fingerprint

Pulsed laser deposition
Dielectric properties
pulsed laser deposition
dielectric properties
Oxygen
oxygen
Tuning
tuning
Crystal structure
Polarization
Epitaxial films
crystal structure
Crystal orientation
Superconducting transition temperature
curves
polarization
Lattice constants
Ferroelectric materials
Hysteresis
Permittivity

Keywords

  • BaTiO3
  • phase transition
  • strain
  • stress
  • thin films

Cite this

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title = "Crystallographic and dielectric properties of highly oriented BaTiO3 films: Influence of oxygen pressure utilized during pulsed laser deposition",
abstract = "The crystal structure of BaTiO3 thin films grown by pulsed laser deposition on MgO substrates was found to be strongly influenced by the oxygen pressure used during growth. Low pressures produced epitaxial films with highly strained out-of-plane lattice parameter c compared to in-plane parameter a, while increasing oxygen pressure resulted in the ratio c/a < 1 with a concomitant increase in polycrystallinity. The dielectric properties varied with changing crystal structure reaching a maximum permittivity value in films near the minimum point of tetragonal distortion and exhibiting relaxor-like behavior in c/a < 1 films close to this point. Hysteresis observed in dielectric tuning loops pointed to the presence of the ferroelectric phase in all films at room temperature. As a result of high electric field poling treatment at 300 °C, the tunability generally increased and initially symmetric tuning curves became asymmetric. The tuning curve in c/a < 1 samples became nearly linear, supporting the premise of polarization reorientation with changing deposition condition. Phase transitions to the paraelectric phase were highly suppressed and shifted upwards in temperature from the bulk transition temperature of 130 to ∼250 °C in strongly c-oriented films. Moderate shifts in oxygen working pressure were demonstrated to produce films with very different properties thereby offering convenient means for strain engineering and control of preferred crystal orientation and polarization direction of highly oriented BTO films.",
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author = "Jussi Hiltunen and D. Seneviratne and H.L. Tuller and J. Lappalainen and V. Lantto",
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Crystallographic and dielectric properties of highly oriented BaTiO3 films : Influence of oxygen pressure utilized during pulsed laser deposition. / Hiltunen, Jussi (Corresponding Author); Seneviratne, D.; Tuller, H.L.; Lappalainen, J.; Lantto, V.

In: Journal of Electroceramics, Vol. 22, No. 4, 2009, p. 395-404.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Crystallographic and dielectric properties of highly oriented BaTiO3 films

T2 - Influence of oxygen pressure utilized during pulsed laser deposition

AU - Hiltunen, Jussi

AU - Seneviratne, D.

AU - Tuller, H.L.

AU - Lappalainen, J.

AU - Lantto, V.

PY - 2009

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N2 - The crystal structure of BaTiO3 thin films grown by pulsed laser deposition on MgO substrates was found to be strongly influenced by the oxygen pressure used during growth. Low pressures produced epitaxial films with highly strained out-of-plane lattice parameter c compared to in-plane parameter a, while increasing oxygen pressure resulted in the ratio c/a < 1 with a concomitant increase in polycrystallinity. The dielectric properties varied with changing crystal structure reaching a maximum permittivity value in films near the minimum point of tetragonal distortion and exhibiting relaxor-like behavior in c/a < 1 films close to this point. Hysteresis observed in dielectric tuning loops pointed to the presence of the ferroelectric phase in all films at room temperature. As a result of high electric field poling treatment at 300 °C, the tunability generally increased and initially symmetric tuning curves became asymmetric. The tuning curve in c/a < 1 samples became nearly linear, supporting the premise of polarization reorientation with changing deposition condition. Phase transitions to the paraelectric phase were highly suppressed and shifted upwards in temperature from the bulk transition temperature of 130 to ∼250 °C in strongly c-oriented films. Moderate shifts in oxygen working pressure were demonstrated to produce films with very different properties thereby offering convenient means for strain engineering and control of preferred crystal orientation and polarization direction of highly oriented BTO films.

AB - The crystal structure of BaTiO3 thin films grown by pulsed laser deposition on MgO substrates was found to be strongly influenced by the oxygen pressure used during growth. Low pressures produced epitaxial films with highly strained out-of-plane lattice parameter c compared to in-plane parameter a, while increasing oxygen pressure resulted in the ratio c/a < 1 with a concomitant increase in polycrystallinity. The dielectric properties varied with changing crystal structure reaching a maximum permittivity value in films near the minimum point of tetragonal distortion and exhibiting relaxor-like behavior in c/a < 1 films close to this point. Hysteresis observed in dielectric tuning loops pointed to the presence of the ferroelectric phase in all films at room temperature. As a result of high electric field poling treatment at 300 °C, the tunability generally increased and initially symmetric tuning curves became asymmetric. The tuning curve in c/a < 1 samples became nearly linear, supporting the premise of polarization reorientation with changing deposition condition. Phase transitions to the paraelectric phase were highly suppressed and shifted upwards in temperature from the bulk transition temperature of 130 to ∼250 °C in strongly c-oriented films. Moderate shifts in oxygen working pressure were demonstrated to produce films with very different properties thereby offering convenient means for strain engineering and control of preferred crystal orientation and polarization direction of highly oriented BTO films.

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KW - phase transition

KW - strain

KW - stress

KW - thin films

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