Ferroelectric, Piezoelectric and Dielectric Behaviors of CoO‐ and Fe₂O₃‐Doped BCZT Ceramics

Abstract

This study investigates the effect of CoO and Fe2O3 dopant on phase, microstructure and ferroelectric properties of BCZT ceramics with the formula of Ba0.85Ca0.15Zr0.1(Ti1‐xCox)0.9O3 and Ba0.85Ca0.15Zr0.1(Ti1‐xFex)0.9O3 where x = 0, 0.01, and 0.03. The XRD patterns presented that the pure perovskite phases are observed regardless of the amount of CoO and Fe2O3 added. Rietveld analysis shows that the tetragonal phase is observed in all patterns and the unit cell volume slightly expanded by the CoO addition while it is distorted with increasing Fe2O3 addition. The average grain sizes decreased upon CoO and Fe2O3 addition. It is found that the doping of CoO and Fe2O3 caused the transition temperature to shift to lower temperature. The optimum ferroelectric and dielectric properties can be achieved for the BCZT‐0.01Co ceramics. This study shows that while small doping with Co and Fe can enhance different properties of BCZT with lower processing temperature, the properties should be further optimized by chemical modification.

Band gap narrowing and magnetic properties of transition‐metal‐doped Ba0.85Ca0.15Ti0.9Zr0.1O3 lead‐free ceramics

“…There are still mixed phases in BCZTM, whereas only the R phase is observed in BCZTF, BCZTC, and BCZTN ceramics . It is expected that ions with radius less than 0.870 Å such as Mn 2+ (0.670 Å), Fe 3+ (0.645 Å), Co 2+ (0.745 Å), and Ni 2+ (0.690 Å) will occupy the B‐site, which may induce contraction of the lattice. In addition, oxygen vacancies caused by charge imbalance promote lattice shrinkage .…”

“…For instance, Sun et al reported that Mn‐doped BCZT ceramic (0.3 mol%) had excellent ferroelectric ( P r = 15.7 μC/cm 2 , E c = 180 V/mm), dielectric (tan δ = 1.04%), and piezoelectric ( d 33 = 308 pC/N) properties. Jaimeewong et al also observed favorable dielectric ( ε r = 4567) and piezoelectric ( d 33 = 276 pC/N) properties in CoO‐ and Fe 2 O 3 ‐doped BCZT ceramics. In addition, owing to their excellent dielectric energy storage performance, BaTiO 3 ‐based materials are of great value in memory and transformer applications and can also be applied to high‐temperature capacitors and pulsed power …”

Dielectric and Energy Storage Properties of Ba(1−x)CaxZryTi(1−y)O3 (BCZT): A Review

“…V 2 O 5 was doped with BCZT by Y. Yang et al and solid state method yielded d 33 = 466 pC/N, P r = 7.735 μC/cm 2 , ε r = 3104, and tanδ = 0.03, implying favorable applications for lead-free piezoelectric ceramics [50]. Some other methods like surfactant-assisted solvothermal processing [55,56,57,58,59,60,61,62,63,64,65,66,67,68,69] oxide-mixed method [56], citrate method [51,52,53,54,55,56,57,58], ceramic route [51], mixed oxide (and carbonates) method [70,71,72], spark plasma sintering technique [73], and Pechini polymeric method [74] were also employed.…”

“…Jaimeewong et al investigated the effect cobalt oxide (CoO) and iron oxide (Fe 2 O 3 ) as dopants on dielectric properties of BCZT and found that the BCZT-0.01Co ceramics presented the finest properties, that is, d33 = 276 pC/N and εr= 4567. The Co doped BCZT ceramics could be employed to prepare lead-free materials with striking properties as shown in the Figure 9 [71].…”

“…Dielectric versus temperature at 1 kHz ( a ) and piezoelectric constant as a function of dopant concentration ( b ). Reprinted with permission from [71]. Copyright 2018 WILEY-VCH Verlag GmbH & Co.…”