Third ferroelectric phase in PMNT single crystals near the morphotropic phase boundary composition

Abstract

In the principle of optical crystallography and crystal symmetry, it is found that at room temperature, the 0.67 PMN-0.33 PT crystals near the morphotropic phase boundary composition present not only a rhombohedral 3m phase but also a monoclinic m phase with various angles of polarization rotation, the third ferroelectric phase in the PMN-PT solid solution system. The polarization rotation readily driven by composition suggests that it can be easily induced by electric field as well, thereby providing the structure base of the ultrahigh piezoelectric performance of 0.67 PMN-0.33 PT single crystals.

Perturbed angular correlation study of 181Ta-doped PbTi1−xHfxO3 compounds

“…25 Hf 0 . 75 0 3 In Fig. 2 some spin precession curves for this composition above and below T c are shown.…”

“…50 H 0 . 50 0 3 In Fig. 4 out previously this composition lies on the morphotropic phase transition, where tetragonal, monoclinic and rhombohedral structures can coexist at low temperatures [14,30].…”

“…It has been observed that almost all the mixtures ABB'0 3 perovskites have the same crystalline structure at RT as that of the major proportion AB0 3 or AB'0 3 simple perovskite forming the alloy has. In PTH the mix of the primary oxides PT and PH produces at room pressure a tetragonal structure for Ti rich compositions.…”

“…Perovskite-type compounds with chemical formula AB0 3 have been the subject of several studies due to their fascinating electrical and magnetic properties such as ferro and antiferroelectricity, superconductivity, piezoelectricity and colossal magneto resistance. These compounds are suitable for a wide variety of applications in microelectronics.…”

“…As the temperature decreases, these compounds exhibit phase transitions to structures of lower symmetry, and their phase diagrams are strongly dependent on the characteristics of the A, A', B and B' elements. In these phase transitions, the atomic displacements from their ideal positions in the cubic structure are relatively small [1][2][3][4][5][6]. It has been observed that these materials can contain oxygen vacancies [7].…”