Grain size dependent phase transition and superparaelectric behavior of ferroelectric BST

作者：Mondal R A^*; Murty B S; Murthy V R K

来源：Physica B: Condensed Matter , 2015, 461: 10-16.

DOI：10.1016/j.physb.2014.12.011

• High energy ball milling
• Diffuse phase transition
• Polar nano-regions
• Superparaelectric behavior

In this article, we investigate the grain size dependent phase transition and polarization behavior of ferroelectric Ba0.9Sr0.1TiO3 (BST). Starting with nanocrystalline powders (crystalline size approximate to 22 nm), various grain sizes were obtained in nano-submicron domain (202-745 nm) by regulating the sintering temperatures (T-sin) in the range of 1050-1300 degrees C. All samples were found to possess diffuse phase transition characteristics with frequency independent broad dielectric maxima near transition temperature due to the lattice strain contribution. Dielectric stiffness showed tarnished step-like anomalous behavior in the paraelectric state for T-sin > 1200 degrees C due to the existence of polar (superparaelectric) nano-regions generated by local polarization by off-centered Ti4+ ions exhibiting an exceptionally rare delicate polarization hysteresis loop.

• 出版日期2015-3-15