We investigated changes in domain structures induced by a partial substitution of Ti for Mn in multiferroic YMnO3 by transmission electron microscopy (TEM). In the ferroelectric phase of YMnO3 at room temperature, there exist 180-degree ferroelectric (FE) domain structures of a micrometer size. On substituting Ti for Mn, the size of FE domains becomes fragile and, at approximately x = 0.175 in YMn1-xTixO 3, the size can be estimated to be 10-20nm. On further substitution, it is found that a structural phase transition from a hexagonal P63 cm structure to a new rhombohedral R3̄c one takes place at approximately x = 0.20. In YMn1-xTixO3 with 0.20 < x < 0.40, these two distinct structures (the hexagonal P63 cm and rhombohedral R3̄c structures) coexist and this coexistence should have some strong effect on the ferroelectric properties such as the magnetocapacitance effect found in Ti-substituted YMnO3.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版ステータス||Published - 2005 9 22|
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