Search

Lead free 0.60 (Na 0.5-x K x Bi 0.5 TiO 3) – 0.40 (SrTiO 3) perovskite ferroelectric ceramics were synthesized effectively by a conventional solid-state reaction root. X – ray diffraction and Rietveld refinement revealed the co-existence of dual phase crystal symmetries for the ceramics around the morphotropic phase boundary in all samples. The coexistence of rhombohedral (R 3 c) and cubic (P m 3 m) phases occurred up to the dopant concentration x = 0.07, succeeding a tetragonal (P 4 b m) with cubic (P m 3 m) symmetries were observed for higher dopant concentrations x = 0.12 and 0.15 respectively. SEM micrographs indicate that the formation of well packed dense microstructure with the nonuniform distribution. Temperature dependent dielectric measurement provoke the dielectric relaxation at low temperature near at depolarization temperature (T d). And then, the incorporation of ST in NKBT host matrix triggers the shifting of Curie temperature (T m) towards the low temperatures. A stable relaxor ferroelectric like behavior up to the dopant concentration x = 0.07, and antiferroelectric like relaxor behavior was triggered progressively up to x = 0.15 was observed through in P-E loop studies. The electric field dependent recoverable energy storage performance at room temperature was calculated and a significant energy storage density (W r e c ) and energy storage efficiency (η) values noticed for x = 0.15 ceramic, which shows the x = 0.15 ceramic optimistic for energy storage applications in dielectric capacitors. Fig. 1S: Systematic transformation of P – E hysteresis shape from relaxor ferroelectric (RFE) to antiferroelectric like relaxor (AL - RF) nature stimulated by K substitution 0.6(Na 0.5-x K x Bi 0.5 TiO 3) – 0.4 (SrTiO 3) (x = 0.03 to 0.15) from x = 0.03 to 0.15. [Display omitted] • Potassium (K+) ion substituted 0.60 (Na0.5-xKxBi0.5TiO3) – 0.40 (SrTiO3) (0.03 ≤ x ≤ 0.15) lead free ferroelectric ceramics were synthesized by a conventional solid-state synthesis. • Rietveld refinement confirms the coexistence of rhombohedral (R3c) and cubic (Pm3m) for x = 0.03, 0.05, and 0.07 ceramics and for higher compositions (x = 0.12 to 0.15) the coexistence of tetragonal (P4bm) and cubic (Pm3m) have been observed. • The evolution in Raman modes and surface morphology studies also correlated to phase transitions and corroborated the XRD findings. • A clear low temperature dielectric relaxation in the vicinity of depolarization temperature was noticed for all the ceramics due to the cationic disorder at A – site. • With the K modification in NKBT – ST lattice relaxor like behavior can be triggered up to x = 0.07, and AL – RF behavior was progressively noted for x = 0.15 ceramic. • The ceramic x = 0.15 with predominated AL – RF behavior has achieved a recoverable Wrec = 0.5562 J/cm3 energy density with the appreciable energy storage efficiency of about 94%. [ABSTRACT FROM AUTHOR]