Elastic softening near the phase transitions in (1 - X) Bi1/2Na1/2TiO3-xBaTiO3 solid solutions

Sarir Uddin, Guangping Zheng, Yaseen Iqbal, Rick Ubic, Ngai Yui Chan, Helen Lai Wa Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

10 Citations (Scopus)


Phase transitions in sol-gel-derived (1 - x)(Bi1/2Na1/2TiO3)-xBaTiO3 (0≤x ≤0.06) solid solutions were investigated via dynamic mechanical, dielectric, and ferroelectric analyses. Structural phase transition was observed from both noncentrosymmetric ferroelectric to nonpolar (antiferroelectric) forms (FE-AFE) at temperatures ranging from ∼120 °C to ∼210 °C, and from antiferroelectric to paraelectric forms (AFE-PE) at temperatures ranging from ∼250 °C to ∼320 °C for 0≤x≤0.06. The former transition is accompanied by a significant and broad elastic softening or soft-mode process, and the latter is of typical diffused type. The dynamic mechanical scaling exponent and critical scaling exponent are used to characterize these two phase transitions, respectively. The temperature-dependent polarization showed an abnormal trend unlike other reported ferroelectrics, confirming the presence of two different phases: FE and AFE. The d33 piezoelectric constant increases with increasing x up to the morphotropic phase boundary. It is suggested that the dynamic mechanical scaling exponents could be used to characterize the mobility of the polar domains and the elastic softening processes, which are closely related to abnormal pyroelectric properties and piezoelastic hardening behaviors.
Original languageEnglish
Article number046102
JournalMaterials Research Express
Issue number4
Publication statusPublished - 1 Dec 2015


  • Lead-free ferroelectrics
  • Phase transitions
  • Piezoelectric
  • Pyroelectric
  • Soft mode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Metals and Alloys

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