Structural and Dielectric Properties of PLZT Ceramics Modified with Lanthanide Ions

Abstract

Lanthanide-modified lead lanthanum zirconate titanate (PLZT) ceramics were prepared through a hydroxide coprecipitation method, and the effects of the lanthanide ions on the structural and dielectric properties of the PLZT ceramics were investigated. The substitution site of the lanthanide ions was found to change from the A site to the B site with decreased lanthanide ionic radius by comparing theoretically calculated and experimentally measured unitcell volumes and densities. The variation of structural and dielectric properties in the lanthanide-modified PLZT series was highly correlated to the change of substitution site, leading to the compositional change of the unit cell. Raman spectra showed that the B-site local structures were affected by the substitution type.

Design and Development for Capacitive Humidity Sensor Applications of Lead-Free Ca,Mg,Fe,Ti-Oxides-Based Electro-Ceramics with Improved Sensing Properties via Physisorption

“…Most of these materials are lead (Pb)-based compounds such as lead magnesium niobate (PbMg 1/3 Nb 2/3 O 3 ), lead titanate (PbTiO 3 ) and lead zirconate titanate (PbZr 1−x Ti x O 3 ) [29,30,31] and so on. Pb-based ceramics such as PbTiO 3 , Ca x Pb 1−x TiO 3 , Li-Ca 0.3 Pb 0.65 TiO 3 have been used as humidity sensors in many studies [32,33], but despite their substantial advantageous dielectric, capacitive and ferroelectric properties, these Pb-based compounds are toxic and hazardous to environment and human health.…”

“…The CMFTO electro-ceramics were prepared by an innovative solid-state step-sintering process to get the desired morphology with lower density and high porosity. This facile synthesis process is convenient, eco-friendly and easily controlled, compared to other synthesis techniques [29,30,31,32,33]. In this route, cheap raw materials like solid titania (TiO 2 ) and other metal ions from magnesium carbonate (MgCO 3 ), hematite (Fe 2 O 3 ), and calcium oxide (CaO) have been taken in solution form.…”

Piezoelectric ceramics in ultrasound

“…The complete lanthanide series offers interesting possibilities for engineering piezoelectric properties. [5,6] The lower atomic number lanthanide elements have larger ionic radii and substitute on the A-sites while the higher atomic number lanthanide elements, which have smaller ionic radii, substitute on the Bsites. The intermediate ionic radii for the elements in the middle of the lanthanide series enables them to substitute into the A-or B-sites.…”

Synthesis of Pb1−xRxZr0.65Ti0.35O3 (x=0.05, 0.10 and 0.15; R=Ce, Pr and Nd) powders by Gel Entrapment Technique and study on their thermo-physical and electrical properties

“…While there have been substantial improvements in many of the properties of PZT using acceptor and donor dopants, it is important to garner greater understanding and control over the properties of ferroelectric materials. Although a great deal of research has focused on doping PZT with La 3+ [5,7] and a number of the other individual lanthanide (Ln 3+ ) cations, few systematic Ln doping PZT studies have been reported on ceramics [8][9][10]. Initially, it was important to discern where the Ln dopants would most likely reside in the ABO 3 structure (i.e., A-or B-site dopants).…”

“…As a starting rationale, the rules of Goldschmidt suggest that dopants will reside on a specific lattice site (either A or B) if a dopant ion's radius is within 15% of the replaced ion [11]. Additionally, it has been shown that the Ln cations will occupy both the A and B sites [5,[8][9][10]12,[13][14][15] but the preference for B-site occupancy increases as the radius of the dopant decreases [8,9,14].The decrease in cation size from 1.17Å (La) to 1.00Å (Lu) [16] results in a transition from A-site (rPb 2+ = 1.2Å) to B-site (rTi 4+ = 0.68Å, rZr 4+ = 0.79Å) occupancy. For intermediate ionic radii values, shared site occupancy (also termed amphoteric or self-compensating) has been shown for trivalent dopants in other perovskite systems, such as BaTiO 3 [17] and SrTiO 3 , [13] and has been predicted for PZT (95/5) [8,9].…”