Strontium bismuth tantalate

Calcined samples indicated formation of carbonate groups at above 500 C at 700°C, crystalline phases started forming (apparently traces of both a pyrochlore phase and the desired tantalate). Heating at 850 C without soaking led to the crystallization of phase pure SrBi2Ta209. The particles approached sphericity with a porous and agglomerated form, and had an average size of about 60 nm. 

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Abstract A short review is given of the status of MRAMs and FRAMs, summarizing both industry prototype production and university research. This comparison seems especially timely since this month (July 2006) Freescale have announced the first commercial MRAM product (4 Mb), and the race is now fairly even between the Samsung 32 Mb lead zirconate titanate FRAM and the Matsushita 4 Mb strontium bismuth tantalate FRAM. 

This 4 Mb FRAM utilizes lead zirconate titanate (PZT) as the active memory element a similar prototype has been made by Matsushita/Panasonic using strontium bismuth tantalate (SET). A 32-Mb SET memory has more recently been announced by Samsung. Device performances are similar in each case. The PZT device has the advantage that it can be processed at lower temperatures (450 °C, compared with ca. 650 °C for SET) the SET devices have the environmental advantage that they are lead-free. 

Monophosphate tungsten bronzes with pentagonal tunnels NASICON = Sodium super ionic conductor NLO = Nonlinear Optical PLZT = Lead lanthanum zirconium titanate PZT = Lead zirconium titanate SBT = Strontium Bismuth Tantalate, SrBi2Ta209 SOFC = Solid oxide fuel cell TTB = Tetragonal tungsten bronze YAG = Yttrium iron garnet 3D = Three-dimensional TEOS = Tetraethylorthosilicate. 

A broad range of electronic ceramic materials have been prepared by CSD, but three material systems have dominated the field of ferroelectric thin films. These include the perovskites PbZr03-PbTi03 (lead zirconate titanate PZT), BaTi03-SrTi03 (barimn strontium titanate BST), and the layered perovskite SrBi2Ta209 (strontium bismuth tantalate SBT). The extensive solid solubility ranges... 

C. H. Lu and S. K. Saha, Colloid emulsion of nanosized strontium bismuth tantalate powder,... 

As ceramics based on multicomponent oxides, the following systems were taken into consideration calcium titanosilicate [61], strontium bismuth tantalate [62], barium magnesium tantalite [63], sodium cobalt oxide [64], and muUite [65-78]. 

Calzada, M.L. and Gonzdlez, A. (2005) Tantalum penta-glycolate sol as a precursor of strontium bismuth tantalate ferroelectric thin films. J. Am. Ceram. Soc., 88 (10), 2702. 

Calzada, M.L., Gonzalez, A., Garcia-Lopez, J., and Jimenez, R. (2003) Crystallization, heterostructure, microstructure, and properties of ferroelectric strontium bismuth tantalate films derived from tantalum glycolate solutions. Chem. 

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