Absence of low temperature phase transitions and enhancement of ferroelectric transition temperature in highly strained BaTiO{sub 3} epitaxial films grown on MgO Substrates

Journal Article · Tue Apr 07 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4916717· OSTI ID:22399387

Kumar, Satish; Kumar, Dhirendra; Kumar, Ravi; Sharma, T. K. ^[1]

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1. Semiconductor Physics and Devices Lab, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

Recently, a large enhancement in the ferroelectric transition temperature of several oxides is reported by growing the respective thin films on appropriate substrates. This phenomenon is correlated with high residual strain in thin films often leading to large increase in the tetragonality of their crystal structure. However, such an enhancement of transition temperature is usually limited to very thin films of ∼10 nm thickness. Here, we report growth of fully strained epitaxial thin films of BaTiO{sub 3} of 400 nm thickness, which are coherently grown on MgO substrates by pulsed laser deposition technique. Conventional high resolution x-ray diffraction and also the reciprocal space map measurements confirm that the film is fully strained with in-plane tensile strain of 5.5% that dramatically increases the tetragonality to 1.05. Raman measurements reveal that the tetragonal to cubic structural phase transition is observed at 583 K, which results in an enhancement of ∼200 K. Furthermore, temperature dependent Raman studies on these films corroborate absence of all the low temperature phase transitions. Numerical calculations based on thermodynamical model predict a value of the transition temperature that is greater than 1500 °C. Our experimental results are therefore in clear deviation from the existing strain dependent phase diagrams.

• OSTI ID: 22399387
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BARIUM COMPOUNDS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ENERGY BEAM DEPOSITION
EPITAXY
FERROELECTRIC MATERIALS
LASER RADIATION
MAGNESIUM OXIDES
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PULSED IRRADIATION
STRAINS
SUBSTRATES
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
THIN FILMS
TITANATES
TRANSITION TEMPERATURE
X-RAY DIFFRACTION