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Influence of Surface Transition Layers on Phase Transformation and Pyroelectric Properties of Ferroelectric Thin Film |
| SUN Pu-Nan1,2, LÜ Tian-Quan1, CHEN Hui1, CAO Wen-Wu 1,3 |
| 1Center of Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 1500012Department of Physics, Heilongjiang University, Harbin 1500803Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA |
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| Cite this article: |
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SUN Pu-Nan, LÜ, Tian-Quan et al 2008 Chin. Phys. Lett. 25 3422-3425 |
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Abstract Taking into account surface transition layers (STLs), we study the phase transformation and pyroelectric properties of ferroelectric thin films by employing the transverse Ising model (TIM) in the framework of the mean field approximation. The distribution functions representing the intra-layer and inter-layer couplings between the two nearest neighbour pseudo-spins are introduced to characterize STLs. Compared with the results obtained by the traditional treatments for the thin films using only the single surface transition layer (SSL), it is shown that the STL model reflects a more realistic and comprehensive situation of films. The effects of various parameters on the phase transformation properties have shown that STL can make the Curie temperature of the film higher or lower than that of the corresponding bulk material, and the thickness of STL is a key factor influencing the film properties. For a film with definite thickness, there exists a critical STL thickness at which ferroelectricity will disappear when the intra-layer and inter-layer interactions are weak.
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77.80.Bh
77.55.+f
77.80.Dj
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Received: 19 April 2008
Published: 29 August 2008
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