Negative thermal expansion in the PbTi1–xFex O3 system

Abstract

AbstractMultiferroic magnetoelectric PbTi1–x Fex O3 compounds were prepared using a solid‐state reaction method in the composition range 0 ≤ x ≤ 0.15. The temperature dependence of lattice parameters of PbTi1–x Fex O3 was determined from high‐temperature X‐ray diffraction. The average volumetric thermal expansion coefficient of the tetragonal phase increases from –1.99 × 10–5 °C–1 for PbTiO3 to –1.13 × 10–5 °C–1 for PbTi0.90Fe0.10O3. The negative thermal expansion and the Curie temperature (TC) of PbTiO3 are reduced by the introduction of Fe. Raman spectral measurements show a softening behaviour for A1(1TO) and A1(2TO) of PbTi1–x Fex O3 with increasing Fe concentration, which means that the decrease in both TC and c /a is due to the reduced spontaneous polarization. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)