Effect of La³⁺-donor substitution on structural, micro structural, dielectric and ferroelectric characteristics of BLNT-BZT solid solutions

ABSTRACT

Lanthanum (La)-modified 0.93(Bi_0.5−xLa_xNa_0.5TiO₃)–0.07(BaTi_0.96Zr_0.04O₃) $\left(0.00\le x\le 0.08\right)$ (Abbreviated as BLNT-BZT) ceramics were synthesized (close to MPB) by using conventional solid state route. The structural phase purity of ceramics was confirmed by using room temperature (RT) X-ray diffraction. The structural phases coexistence was analyzed with different duel phase model and bring out the amount of phase contribution quantitatively with the help of Rietveld refinement technique. The X-rays diffraction studies revealed that coexisting of minor tetragonal (P4mm) phase evolution along with major monoclinic structural (Cc) phase. Moreover, the above affirmation was clarified from Raman studies, observed that TiO₆ reflection at 500–600 cm⁻¹ splitting occurs resides the presence of MPB of ceramics. With the substitution of La in BNT–BZT induces the gradual change in the average grain size and non-uniform distribution was observed from the surface morphology. The dielectric anomalies of these BLNT-BZT ceramics show broad dielectric anomaly near the maximum dielectric constant, which reflects the diffuse phase transition behavior. The RT P-E loops were observed in slim and slanted shape, replicates the enhanced properties due to the phase additive behavior near the MPB.

KEYWORDS:

• Ferroelectric
• dielectric phase transitions
• Cuires Weiss law
• strcutural and microstructural
• saturation polarization
• tetragonal phase
• antiferroelectrics