Vol.4 No.5 (September 2014)
Dielectric Effect of Distributed Curie Temperature in a Model of Cubic Core-Shell Grain
吴 静 ：湖北大学物理学与电子科学学院，武汉
A model of cubic core-shell grain with the distribution of the Curie temperature is proposed for simulation of the polyhedron core-shell structure to obtain the size related dielectrics. When the shell is a very thin layer with low dielectric constant, the shell has the grain-size effect: dielectric constant decreases and the peak moves to low temperature. When the shell is thick with different dielectric peak from the core one, the contribution of the core to the dielectric constant is a linear relation to the square of it size. The distribution of the Curie temperature will move dielectric peak to high temperature with dropping dielectric constant, and the temperature relation of im-permeability in paraelectric phase can not be expressed by the power-law. Ferroelectrics will have high stability of relation of dielectric constant with temperature for the combination of the shell in linear distribution and the core in Gaussian distribution. It is the square of spontaneous polariza-tion in ferroelectrics that has the same function as dipole in dielectrics for contribution to the complex dielectric constant, and therefore a temperature dependent dielectric loss of the distri-bution of the Curie temperature is derived.
吴 静 , 曹万强 , 尚勋忠 (2014) 立方核壳晶粒模型的分布介电效应。 材料科学， 4， 211-217. doi: 10.12677/MS.2014.45030
 Wada, N., Hiramatsu, T., Tamura, T. and Sakabe, Y. (2008) Investigation of grain boundaries influence on dielectric properties in fine-grained BaTiO3 ceramics without the core-shell structure. Ceramics International, 34, 933-937.
 Papet, P., Dougherty, J.P. and Shrout, T.R. (1990) Particle and grain size effects on the dielectric behavior of the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3. Journal of Materials Research, 5, 2902-2909.
 舒明飞, 尚玉黎, 陈威, 曹万强 (2012) 核壳结构对弛豫铁电体介电行为的影响. 物理学报, 17, Article ID: 177701.
 尚玉黎, 舒明飞, 陈威, 曹万强 (2012) 钛酸钡基施主掺杂弛豫铁电体介电弥散的唯象分析. 物理学报, 19, Article ID: 197701.
 甘永超, 曹万强 (2013) 铁电相变中极化与介电性的随机场效应. 物理学报, 12, Article ID: 127701.
 Emelyanov, A.Y., Pertsev, N.A., Hoffmann-Eifert, S., Böttger, U. and Waser, R. (2002) Grain-boundary effect on the curie-weiss law of ferroelectric ceramics and polycrystalline thin films: Calculation by the method of effective medium. Journal of Elec-troceramics, 9, 5-16.
 Haertling, G.H. (1999) Ferroelectric ceramics: History and technology. Journal of American Ceramic Society, 82, 797- 818.
 屈少华, 曹万强 (2014) 球形无规键无规场模型研究弛豫铁电体极化效应. 物理学报, 4, Article ID: 047701.
 Chen, X.Q. and Fang, C. (2013) Study of electrocaloric effect in barium titanate nanoparticle with core-shellmodel. Physica B: Condensed Matter, 415, 14-17.
 Fang, C., Zhou, D.X. and Gong, S.P. (2011) Core-shell structure and size effect in barium titanate nanoparticle. Physica B: Condensed Matter, 406, 1317-1322.
 Zhao, Z., Buscaglia, V., Vivian, M., Buscaglia, M.T., Mitoseriu, L., Testino, A., et al. (2002) Grain-size effects on the ferroelectric behavior of dense nanocrystalline BaTiO3 ceramics. Physics Review B, 70, Article ID: 024107.
 Lacourse, B.C. and Amarakoon, V.R.W. (1995) Characterization of the firing schedule for positive temper-ature coefficient of resistance BaTiO3. Journal of American Ceramic Society, 78, 3352-3356.
 Cheng, H.-F., Lin, T.-F., Hu, C.-T., et al. (1993) Effect of sintering aids on microstructures and PTCR characteristics of (Sr0.2Ba0.8)TiO3 ceramics. Journal of American Ceramic Society, 76, 827-832.
 Ho, I.-C. and Hsieh, H.-L. (1993) Influence of po-tassium on preparation and performance of PTC resistors. Journal of American Ceramic Society, 76, 2385-2388.
 Cao, W.Q. and Chen, W. (2014) Dielectric properties of Y2O3 donor-doped Ba0.8Sr0.2TiO3 ceramics. Materials Chemistry and Physics, 143, 676-680.
 Kim, C.H., Park, K.J., Yoon, Y.J., et al. (2008) Role of yttrium and magnesium in the formation of core-shell structure of BaTiO3 grains in MLCC. Journal of the European Ceramic Society, 28, 1213-1219.
 Wang, X.H., Chen, R.Z., Gui, Z.L., et al. (2003) The grain size effect on dielectric prop-erties of BaTiO3 based ceramics. Materials Science and Engineering B-Advanced Functional Solid-State Materials, 99, 199-202.
 Arlt, G., Hennings, D. and With, G. (1985) Dielectric properties of fine-grained barium titanate ceramics. Journal of Applied Physics, 58, 1619-1625.
 Shakh, A.S., Vest, R.W. and Vest, G.M. (1989) Dielectric properties of ultrafine grained BaTiO3. IEEE Transactions on Ultrasonic Ferroelectrics and Frequency Control, 36, 407-412.
 Kishi, H., Kohzy, N., Iguchi, Y., et al. (2000) Study of occupational sites and dielectric properties of Ho-Mg and Ho- Mn substituted BaTiO3. Japanese Journal of Applied Physics Part 1—Regular Papers Short Notes & Rev, 39, 5533- 5537.
 Li, B., Zhang, S., Zhou, X., Wang, S. and Chen, Z. (2007) Preparation of BaTiO3-based ce-ramics by nanocomposite doping process. Journal of Materials Science, 42, 2090-2096.
 钟维列 (1996) 铁电物理学. 科学出版社, 北京, 73.
 Bratkovsky, A.M. and Levanyuk, A.P. (2005) Smearing of phase transition due to a surface effect or a bulk in homogeneity in ferroelectric nanostructureshys. Physics Review Letters, 94, Article ID: 107601.