The Effect of Cu2+ Substitution on the Properties of BNKLT Lead-Free Ceramics Fabricated by the Solid-State Combustion Technique. Issue 1 (12th February 2021)

• Record Type: Journal Article
• Authors: Kornphom, Chittakorn; Bhupaijit, Pamornnarumol; Mala, Luxsanaree; Bongkarn, Theerachai; Charoenthai, Nipaphat
• Is Part Of: Integrated ferroelectrics. Volume 214:Issue 1(2021)
• Page Start: 46
• Page End: 55
• Publication Date: 2021-02-12
• Subjects: BNKLT-xCu ceramics -- solid-state combustion technique -- dielectric behavior -- ferroelectric properties; Ferroelectric devices -- Periodicals; Integrated circuits -- Periodicals; 537.244805
• DOI: 10.1080/10584587.2020.1857177
• Languages: English
• ISSNs: 1058-4587

Abstract

Abstract: This article reports the effect of Cu 2+ substitution on the phase formation, morphology and electrical behavior of Bi0.5 Na0.34 K0.11 Li0.05 Ti(1-x) Cux O3 with 0 ≤ x ≤ 0.020 (BNKLT-xCu) ceramics prepared by the solid state combustion technique with glycine used as the fuel. All samples were prepared with a calcination temperature and a sintering temperature of 750 °C and 1025 °C, respectively for 2 h. The XRD results of all compositions revealed a single perovskite structure and that Cu 2+ diffused efficiently into B-sites of the lattice, producing a BNKLT-xCu solid solution. The phase formation of the BNKLT-xCu ceramics showed coexisting rhombohedral (R) and tetragonal (T) phases in all samples. The highest measured density of the BNKLT ceramics was 5.99 g/cm 3 and good dielectric properties measured at the temperature of the maximum dielectric constant (ε m = 4723 and tanδ = 0.054), were obtained by the sample with Cu 2+ substituted at x = 0.010. The BNKLT-xCu ceramics with Cu 2+ ≥ 0.005 showed pinched P-E loops, and the negative strain of the S-E loops started to disappear, owing to the Cu 2+ induced transformation from the ferroelectric ( FE ) phase to the ergodic relaxor ( ER ) phase. With Cu 2+ levels of 0.010, the d*33 value increased to 705 pm/V, indicating that this sample was near the FE–ER phase boundary with induced high strain. Substituting an appropriate amount of Cu 2+ improved the densification of BNKLT-xCu ceramics as capillary forces in the liquid phase during sintering pulled the grains together, which increased the εm values.