Lanthanum zirconate

PZT (lead zirconate titanate) and PLZT (lead lanthanum zirconate titanate) combine ferroelectic, optical, and electronic properties and are used in optoelectronic and piezoelectric devices. Powders for hot pressing produced by CVD are being investigated. 

Lead iodide, 14 785-786 Lead-lag systems, 14 408 Lead lanthanum zirconate titanate (PLZT), 5 583 22 713... 

A wide array of ferroelectric, piezoelectric and pyroelectric materials have titanium, zirconium and zinc metal cations as part of their elemental composition Many electrical materials based on titanium oxide (titanates) and zirconium oxide (zirconates) are known to have structures based on perovskite-type oxide lattices Barium titanate, BaTiOs and a diverse compositional range of PZT materials (lead zirconate titanates, Pb Zr Tij-yOs) and PLZT materials (lead lanthanum zirconate titanates, PbxLai-xZryTii-yOs) are among these perovskite-type electrical materials. 

Care has to be taken in selecting materials for the die and punches. Metals are of little use above 1000 °C because they become ductile, and the die bulges under pressure so that the compact can only be extracted by destroying the die. However, zinc sulphide (an infrared-transparent material) has been hot pressed at 700 °C in stainless steel moulds. Special alloys, mostly based on molybdenum, can be used up to 1000 °C at pressures of about 80 MPa (5 ton in-2). Alumina, silicon carbide and silicon nitride can be used up to about 1400 °C at similar pressures and are widely applied in the production of transparent electro-optical ceramics based on lead lanthanum zirconate as discussed in Section 8.2.1. 

Lead lanthanum zirconate titanates (PLZT) containing 3-12 mol. % La and 5-30 mol. % Ti form a class of ceramics with important dielectric, piezoelectric and electro-optic properties. They may contain vacancies on B as well as A sites and have a remarkable facility for changing their polar states under the influence of applied fields. 

Crystalline, lead-containing ceramics generally fall within the category of materials called PZTs/PLZTs, which are lead-(lanthanum) zirconate titanates. These materials... 

Some ceramics are transparent to light of specific frequencies. These optical ceramics are used as windows for infrared and ultraviolet sensors and in radar installations. However, optical ceramics are not as widely used as glass materials in applications in which visible light must be transmitted. An electro-optic ceramic such as lead lanthanum zirconate titanate is a material whose ability to transmit light is altered by an applied voltage. These electro-optic materials are used in color filters and protective goggles, as well as in memory-storage devices. 

Seth, V. K., Schulze, W. A., and Condrate, R. A., Sr. Vibrational spectral characterization of a lead lanthanum zirconate titanate during various stages of sol-gel processing. Spectra. Lett., 24, 1299 (1991). 

Abe Y, Kakegawa K (2002) Fabrication of optically transparent lead lanthanum zirconate titanate ((Pb, La)(Zr, Ti)03) ceramics by a three-stage-atmospheie-sintering technique. J Am Ceram Soc 85 473-475... 

Kong LB, Ma J, Zhang TS, Zhang RE (2002) Transparent lead lanthanum zirconate titanate craamics dtaived from oxide mixture via a repeated anneaUng process. J Mater Res 17 929-932... 

Shvartsman VV, KhoUdn AL, Orlova A, Kiselev D, Bogomolov AA, Sternberg A (2005) Polar nanodomains and local ferroelectric phenomena in relaxor lead lanthanum zirconate titanate ceramics. Appl Phys Lett 86 202937... 

Kong LB, Ma J, Zhang RF, Zhang TS (2002) Fabrication and characterization of lead lanthanum zirconate titanate (PLZT7/60/40) ceramics from oxides. J Alloy Compd 339 167-174... 

Doping PZT with lanthanum ions (La replaces Pb ) shifts the morphotropic boundary to higher x-values and lowers the Curie temperature of the oxidic alloy. At 5% La, the Curie temperature can even drop below room temperature if X is high enough. The solid has become cubic and paraelectric and no longer has a permanent electric dipole moment at room temperature but is very polarizable. This material is called PLZT (short for lead lanthanum zirconate titanate) and is used for its nonlinear optical properties, e.g., in doubling the frequency of laser radiation. 

Transparent ferroelectric single crystals are traditionally used for electro-optic applications. Since the optical transparency was first discovered in lead-lanthanum-zirconate-titanate (PLZT), ferroelectric ceramics have been investigated in great depth such that, today, their characteristics allow them to compete with single crystals for certain electro-optic applications. The electro-optic properties of PLZT compositions are intimately related to their ferroelectric properties. Variations in ferroelectric polarization with an electric field, such as in a hysteresis loop, also affect the optical properties of the material. 

Sangeetha NM, van Veggel FCJM (2009) Lanthanum silicate and lanthanum zirconate nanoparticles co-doped with Ho and Yb matrix-dependent red and green upconversion emissions. J Phys Chem C 113 14702... 

Pakhare, D., Shaw, C., Haynes, D., Shekhawat, D., Spivey, J. (2013). Effect of reaction temperature on activity of Pt- and Ru-substituted lanthanum zirconate pyrochlores for dry (CO2) reforming of methane (DRM). Journal ofC02 Utilization, 1, 37—42. 

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