Phase development and electrical properties of Pb(Mg_1/3Nb_2/3)O₃‐PbTiO₃ ceramics prepared by partial oxalate route

Abstract

(1 − x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 (PMN‐PT, x = 0.2–0.4) ferroelectric (FE) ceramics were prepared by the partial oxalate route. The synthesized PMN‐PT ceramics exhibit high density and densified microstructure although slight content of pyrochlore phase impurity exists. With the increase of PbTiO3 (PT) content, the phase structure of the PMN‐PT ceramics changes gradually from rhombohedral perovskite structure, across the morphotropic phase boundary (MPB) composition and to tetragonal perovskite structure. The FE structural phase transition of PMN‐PT changes gradually from the diffused ferroelectric phase transition (FPT) of typical relaxor FEs to nearly first‐order FPT of normal FEs, confirmed by dielectric and FE properties measurements. The PMN‐PT ceramics exhibit excellent dielectric and piezoelectric properties, and fully developed and saturated P–E hysteresis loops, in which the MPB effects are clearly shown by these electrical properties. The MPB composition of the PMN‐PT system is determined locating at x = 0.31–0.33 by XRD measurement and electrical properties measurements.

Large Electrocaloric Effect in Lead-Free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Ceramics Prepared via Citrate Route

“…However, significant investigations have been carried out on ceramics processing by the solid-state sintering method in order to increase T C and understand the mechanisms of ferroelectric phase transition and piezoelectric response origins rather than electrocaloric effects [18,19,20,21]. It is well-known that ceramics synthesis methods and processing conditions, and chemical doping influence phase structure formation and microstructure morphology [22,23], which exert great effects on the electrical properties of the synthesized ceramics via the intrinsic factors correlated with phase structure and lattice distortion and extrinsic factors correlated with microstructure morphology and domain configuration [24,25]. Therefore, 1 wt % Li-doped (Ba 0.85 Ca 0.15 )(Zr 0.1 Ti 0.9 )O 3 (BCZT-Li) ceramics were prepared by the citrate method and the effects of Li doping and citrate method were reported [26,27].…”

Mn Katkılı PIN-PMN-PT Tekil Kristalinin Dielektrik Katsayısı, Relaksiyon Zamanı ve Aktivasyon Enerjisinin Hesaplanması

“…Gevşeme süresi metallerde küçük, yarı iletkenler ve izolatörlerde büyük değerlere sahiptir. Literatürdeki çalışmalarda farklı relaksör-ferroelektrik malzemeler için farklı frekans değerlerinde dielektrik katsayısının değişimleri incelenmiştir, bu ölçüler ile sistemin histerisis davranımı ve süreleri belirlenmiştir (Qian et al, 2013, Sun et al 2016, Cowley at al. 2011).…”

“…Ferroelektrik-rhombohedral fazda, her iki mod içinde sıcaklık artışı ile gevşeme süresinin arttığı, faz geçiş noktasında (TC) süreksiz olduğu görülmüştür (Şekil 4 ve 6). Mn-0.15PIN-0.55PMN-0.30PT kristal malzemesinin gevşeme süresindeki artış diğer ferroelektrik özellik gösteren malzemeler kıyaslandığında daha az değişmektedir (Qian et al, 2013, Sun et al 2016, Cowley at al. 2011.…”

Uncovering microstructure and composition susceptibility of high permittivity ceramic granules to plasma‐induced arc breakdown

“…This attribute is critical to ensure maximum electric field concentration across air gaps to ensure arc breakdown during a surge event (see Figure 1). Of critical importance in PMN–PT ceramic processing is the avoidance of pyrochlore phase content, 26,27 which can drastically lower dielectric constants at higher temperatures even for small levels (e.g., 10%) 25,28 . Similarly, alterations in material composition during operation would be expected to have deleterious effects on dielectric properties and performance stability.…”