Aurivillius phases are a form of

perovskite Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula ). Its name is also applied to the class of compounds which have the same type of crystal structure as (XIIA2+VIB4+X2−3), known as ...

represented by the general formulae is ( Bi₂ O₂)(A_''n''−1B_''n''O_3''n''+1) (where A is a large 12 co-ordinate cation, and B is a small 6 co-ordinate cation). Basically, their structure is built by alternating layers of i₂O₂sup>2+ and pseudo-perovskite blocks, with perovskite layers that are ''n'' octahedral layers in thickness. This crystal structure was first described in 1949 by Swedish chemist

Bengt Aurivillius Bengt Aurivillius (4 December, 1918 in Linköping – 2 May, 1994 in St. Peter's Parish, Malmöhus County) was a Swedish chemist known for his research in metal and mixed oxides. Education and career Aurivillius received his basic scientific educ ...

. The first interest in Aurivillius phases arose from the observation of

ferroelectricity Ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoelectric and pyroelectric, with the add ...

even for the simplest member, Bi₂WO₆ (n=1) of this crystallographic family. The Mo-homologous Aurivillius phase Bi₂MoO₆ was recently investigated as a potential LTCC material. Their oxide ion-conducting properties of Aurivillius phases were first discovered in the 1970s by Takahashi et al., and they have been used too for this purpose ever since. Aurivillius phase oxide materials are a class of lead-free ceramics.

References

Bismuth compounds Perovskites {{Oxide-mineral-stub

See also

References