Publication Date:
2015-08-13
Description:
We report an experimental study of the domain structure of ferroelectric YMnO 3 and YMn 0.9 Fe 0.1 O 3 using polycrystalline samples prepared by direct hydrothermal crystallisation at 240 °C, well below their structural phase transition temperatures. Powder X-ray diffraction shows the expected P 6 3 cm space group for both samples with an increase in a and a small decrease in c with Fe incorporation, consistent with an adjustment of MnO 5 tilting, while XANES spectra at the Mn and Fe K edges show the oxidation state of both metals are maintained at +3 in the doped sample. High resolution TEM shows that curved stripe, annular and vortex domains can all be observed in the YMnO 3 crystals, proving that the structural phase transition is not the only driving force for the occurrence of the annular and vortex domains. Furthermore, the absence of the annular and vortex domains in YMn 0.9 Fe 0.1 O 3 indicates that the tilting state of MnO 5 bipyramids plays an important role in the domain formation. Atomic resolution STEM images confirm that the ferroelectric domain walls correspond to structural antiphase boundaries similar to the crystals made via high temperature solid-state reactions.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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