Design and magnetic properties of new compounds containing iron 2D building blocks of the perovskite type

Using the concept of 2D building blocks we have looked for new compounds containing iron 2D perovskite type building blocks. In that purpose, we have tried to exchange the [Cu2S2] 2D building blocks found in Sr3Fe2Cu2S2O5 by other isostructural blocks such as [Cu2Se2], [Ag2S2], [Ag2Se2] or [Zn2P2]. With a high temperature ceramic method and/or a metathesis reaction we have then succeeded to synthesize Sr3Fe2Cu2Se2O5, Sr3Fe2Ag2S2O5 and Sr3Fe2Ag2Se2O5. Structure refinement from X-ray powder diffraction patterns of Sr3Fe2Cu2Se2O5 and Sr3Fe2Ag2S2O5 have confirmed that the structure of both compounds results from the expected alternated stacking of perovskite [Sr3Fe2O5] and anti-fluorite [Cu2Se2] or [Ag2S2] 2D building blocks. Mössbauer spectroscopy measurements for Sr3Cu2Fe2Se2O5 revealed the presence of Fe3+ high spin within the perovskite [Sr3Fe2O5] block and showed that the magnetic moments of iron are ordered at low temperature. Moreover neutron diffraction experiments have revealed an antiferromagnetic structure (TN≈490K) with iron magnetic moments aligned along the a axis.