Re-entrant-like relaxor behaviour in the new 0.99BaTiO(3)-0.01AgNbO(3) solid solution

Area of Science:

• Materials Science
• Solid State Chemistry
• Ferroelectricity Research

Background:

• Barium titanate (BaTiO3) is a well-known ferroelectric material with distinct phase transitions.
• Relaxor ferroelectrics typically display dielectric relaxation and unique microstructural features.
• Conventional relaxors often originate from cubic phases in complex perovskite structures.

Purpose of the Study:

• To synthesize and characterize a new solid solution: 0.99BaTiO3-0.01AgNbO3.
• To investigate the structural, dielectric, and ferroelectric properties of this material.
• To understand the origin and nature of observed anomalous dielectric behavior.

Main Methods:

• Solid-state reaction method for material synthesis.
• Structural analysis to determine phase composition and transitions.
• Dielectric permittivity measurements as a function of temperature and frequency.
• Ferroelectric property evaluation.

Main Results:

• The 0.99BaTiO3-0.01AgNbO3 solid solution was successfully prepared.
• An additional dielectric permittivity peak was observed around 100°C, distinct from pure BaTiO3 transitions.
• This peak demonstrated dielectric relaxation obeying the Vogel-Fulcher law, indicative of relaxor behavior.
• The relaxor state emerged within the ferroelectric phase, a re-entrant-like phenomenon.
• This relaxor state originated from a tetragonal phase, unlike conventional cubic-phase relaxors.

Conclusions:

• The addition of AgNbO3 induces a unique re-entrant relaxor behavior in BaTiO3.
• This behavior, occurring within the ferroelectric phase and originating from a tetragonal structure, is unprecedented in lead-free ferroelectrics.
• The findings offer new insights into the design and understanding of advanced ferroelectric materials.