Novel Phase Transition in BaPr2Mn2O7
来源期刊：JOURNAL OF RARE EARTHS2006年增刊第2期
论文作者：Hiromi Nakano Naoki Kamegashira
Key words：rare earth manganite; phase transition; transmission electron microscope (TEM);
Abstract: The rare earth manganite BaLn2Mn2O7 (Ln=rare earth element) has a Sr3Ti2O7-type layered perovskite structure with double-block oxygen octahedra belonging to the Ruddlesden-Popper-type homologous series AO(ABO3)2. In Pr-manganite, a novel phase transition was first observed in situ at 1040 K by a thermal transmission electron microscope. At 1040 K, reflections began to split along the c-direction in the selected area diffraction pattern. This indicates that a new phase appears in the original phase matrix; the c length of the new phase is 1.5% longer than that of the original phase. After about 5 min, the original phase disappears. No change in the crystal symmetry (space group I4/mmm) is observed above 1040 K.
Hiromi Nakano1，Naoki Kamegashira2
(1.Ryukoku University, Seta, Otsu 520-2194, Japan;
2.Toyohashi University of Technology, Tenpaku-cho, Toyohashi 441-8580, Japan)
Abstract:The rare earth manganite BaLn2Mn2O7 (Ln=rare earth element) has a Sr3Ti2O7-type layered perovskite structure with double-block oxygen octahedra belonging to the Ruddlesden-Popper-type homologous series AO(ABO3)2. In Pr-manganite, a novel phase transition was first observed in situ at 1040 K by a thermal transmission electron microscope. At 1040 K, reflections began to split along the c-direction in the selected area diffraction pattern. This indicates that a new phase appears in the original phase matrix; the c length of the new phase is 1.5% longer than that of the original phase. After about 5 min, the original phase disappears. No change in the crystal symmetry (space group I4/mmm) is observed above 1040 K.
Key words:rare earth manganite; phase transition; transmission electron microscope (TEM);
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