Materials Science

Losing Layers in Perovskites

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Science  07 Apr 2000:
Vol. 288, Issue 5463, pp. 13
DOI: 10.1126/science.288.5463.13e

The perovskite family of metal oxides includes several technologically interesting materials, such as high-temperature superconductors (HTSCs), colossal magnetoresistance (CMR) materials, and ferroelectrics. Because these compounds usually are synthesized through high-temperature reactions, targeting a particular composition and structure is hard. Schaak and Mallouk incorporated a reducible metal cation (Eu3+) into the “A” site of a layered perovskite (the A sites lie in between the octahedra formed by other metal cations, which occupy the B sites). After ion exchange, reduction with hydrogen yielded three-dimensional perovskites through loss of oxygen, which forced additional bridging of the BO6 octahedra. Although this method was demonstrated for an easily reduced A site cation, it should be possible to reduce B site cations, such as the Mn4+ ions in CMR materials and Cu3+ in HTSCs.—PDS

J. Am. Chem. Soc.122, 2798 (2000).

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