Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films
Ferroelectricity and piezoelectricity are desirable for a variety of high-temperature applications such as actuators and sensors in heat engines, high-temperature manufacturing, and space technologies; however, the material candidates are currently limited. Here, we demonstrate that CaTiO3, the prot...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2019-05-01
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| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/1.5090798 |
| _version_ | 1811337397965684736 |
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| author | Ryan C. Haislmaier Yanfu Lu Jason Lapano Hua Zhou Nasim Alem Susan B. Sinnott Roman Engel-Herbert Venkatraman Gopalan |
| author_facet | Ryan C. Haislmaier Yanfu Lu Jason Lapano Hua Zhou Nasim Alem Susan B. Sinnott Roman Engel-Herbert Venkatraman Gopalan |
| author_sort | Ryan C. Haislmaier |
| collection | DOAJ |
| description | Ferroelectricity and piezoelectricity are desirable for a variety of high-temperature applications such as actuators and sensors in heat engines, high-temperature manufacturing, and space technologies; however, the material candidates are currently limited. Here, we demonstrate that CaTiO3, the prototype perovskite mineral, abundantly found in the Earth, which as a nonpolar material in bulk form, becomes a high-temperature ferroelectric oxide under compressive strain when grown as a thin film. A strain-phase-temperature diagram of CaTiO3 films is created by growing films on various substrates with different in plane strains in order to map out the polar behavior for compressive and tensile strain. Using temperature dependent optical second harmonic generation analysis, we show that tensile strained films exhibit predominantly in-plane polarization with orthorhombiclike point group symmetry with a phase transition below room temperature. On the other hand, compressively strained CaTiO3 films exhibit a near-tetragonal unit cell with a c/a ratio of 1.03, larger than that of classic ferroelectric, e.g., BaTiO3 (c/a ∼ 1.01). These films exhibit a robust and switchable out-of-plane polarization at room temperature, with a ferroelectric transition temperature up to ∼800 K. Density functional theory calculations reveal that compressive strain gives rise to a large out-of-plane displacement of Ti-cations inside the TiO6 octahedral cages and is the major contributor to the calculated polarization of ∼9 µC/cm2. Given that nearly half of the perovskites exhibit the bulk symmetry of CaTiO3, compressive strain tuning of this perovskite family may prove to be a fertile ground for the discovery of strain-induced piezoelectrics and ferroelectrics at high-temperatures. |
| first_indexed | 2024-04-13T17:54:21Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2166-532X |
| language | English |
| last_indexed | 2024-04-13T17:54:21Z |
| publishDate | 2019-05-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj.art-8c960b066f7e4d16bc75130f4c82c9922022-12-22T02:36:35ZengAIP Publishing LLCAPL Materials2166-532X2019-05-0175051104051104-710.1063/1.5090798016904APMLarge tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin filmsRyan C. Haislmaier0Yanfu Lu1Jason Lapano2Hua Zhou3Nasim Alem4Susan B. Sinnott5Roman Engel-Herbert6Venkatraman Gopalan7Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USAAdvanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USADepartment of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USAFerroelectricity and piezoelectricity are desirable for a variety of high-temperature applications such as actuators and sensors in heat engines, high-temperature manufacturing, and space technologies; however, the material candidates are currently limited. Here, we demonstrate that CaTiO3, the prototype perovskite mineral, abundantly found in the Earth, which as a nonpolar material in bulk form, becomes a high-temperature ferroelectric oxide under compressive strain when grown as a thin film. A strain-phase-temperature diagram of CaTiO3 films is created by growing films on various substrates with different in plane strains in order to map out the polar behavior for compressive and tensile strain. Using temperature dependent optical second harmonic generation analysis, we show that tensile strained films exhibit predominantly in-plane polarization with orthorhombiclike point group symmetry with a phase transition below room temperature. On the other hand, compressively strained CaTiO3 films exhibit a near-tetragonal unit cell with a c/a ratio of 1.03, larger than that of classic ferroelectric, e.g., BaTiO3 (c/a ∼ 1.01). These films exhibit a robust and switchable out-of-plane polarization at room temperature, with a ferroelectric transition temperature up to ∼800 K. Density functional theory calculations reveal that compressive strain gives rise to a large out-of-plane displacement of Ti-cations inside the TiO6 octahedral cages and is the major contributor to the calculated polarization of ∼9 µC/cm2. Given that nearly half of the perovskites exhibit the bulk symmetry of CaTiO3, compressive strain tuning of this perovskite family may prove to be a fertile ground for the discovery of strain-induced piezoelectrics and ferroelectrics at high-temperatures.http://dx.doi.org/10.1063/1.5090798 |
| spellingShingle | Ryan C. Haislmaier Yanfu Lu Jason Lapano Hua Zhou Nasim Alem Susan B. Sinnott Roman Engel-Herbert Venkatraman Gopalan Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films APL Materials |
| title | Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films |
| title_full | Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films |
| title_fullStr | Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films |
| title_full_unstemmed | Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films |
| title_short | Large tetragonality and room temperature ferroelectricity in compressively strained CaTiO3 thin films |
| title_sort | large tetragonality and room temperature ferroelectricity in compressively strained catio3 thin films |
| url | http://dx.doi.org/10.1063/1.5090798 |
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