• Rai, Radheshyam

Abstract

<jats:p> In this research paper, we utilized the traditional high-temperature solid-state reaction method to fabricate the K[Formula: see text]Na[Formula: see text]NbO<jats:sub>3</jats:sub>, K[Formula: see text]Na[Formula: see text]NbO<jats:sub>3</jats:sub> and K[Formula: see text]Na[Formula: see text]NbO<jats:sub>3</jats:sub> (abbreviated as KNN-1, KNN-2, and KNN-3, respectively) lead-free ion deficient ceramics for understanding the influence of ionic deficiency on the crystalline structure and dielectric/piezoelectric properties of the samples. X-ray diffraction patterns of these samples exhibited a perovskite tetragonal phase. Dielectric anomalies around 287<jats:sup>∘</jats:sup>C and 471<jats:sup>∘</jats:sup>C were identified as ferroelectric to ferroelectric and ferroelectric to paraelectric-transition temperatures for KNN-2 at 1[Formula: see text]kHz. It was found that the composition KNN-2 exhibit relatively high Curie temperature i.e., 471<jats:sup>∘</jats:sup>C. The conductivity plots confirm that the activation energies are frequency-dependent. The impedance behavior in our ceramic samples can be analyzed with the bulk/grain effect. The slope of [Formula: see text] with temperature shows negative temperature coefficient of resistance (NTCR) type behavior in proposed KNN ceramics material. </jats:p>

Topics

• perovskite
• grain
• phase
• x-ray diffraction
• activation
• Curie temperature