Structural determination of a new phase of monoclinic BaTb2Mn2O7

In situ Transmission Electron Microscopy Observation of Multiple Phase Transition in BaGd2Mn2O7

“…The II–III transition point could be related to the inflection of the electrical conductivity curve against temperature at approximately 620 K 13 . From the SAED patterns, phase III seems to have a close relation with the monoclinic B 112/ m structure that was observed in BaTb 2 Mn 2 O 7 upon annealing 12 . It is expected that one or more phase transitions may occur at temperatures above 1023 K because the symmetry of phase III is still much lower than F 4/ mmm assumed for the prototype.…”

“…Deschizeaux–Cheruy and Joubert were the first to synthesize these manganites (Ln=Nd–Gd) in a N 2 atmosphere 2 . After that, many phases were reported for the oxides, depending on the synthesis or annealing conditions 3–12 . High‐temperature X‐ray diffraction (XRD) analysis, and electrical conductivity and thermal analyses, 3,13,14 revealed phase transitions for the Sm, Eu, Gd, Nd, and Tb compounds, which undergo a transition from orthorhombic to tetragonal on heating.…”

In-situ observation of phase transformations in layered perovskite BaEu2Mn2O7

“…Phase III seems to have a close relation with the monoclinic B112/m structure, which was observed in annealed BaTb 2 Mn 2 O 7 . 9 The complex diffraction pattern was caused by the twinning structure of the monoclinic cell.…”

“…2 Subsequently, many phases were reported for the oxides, depending on the synthesis or annealing conditions. [3][4][5][6][7][8][9] Those annealing conditions were based on the phase transformation of the BaLn 2 Mn 2 O 7 . The phase transformations of the oxides have been investigated by high-temperature X-ray diffraction (XRD), electrical conductivity, and thermal analyses.…”

<i>In Situ</i> Measurement of Phase Transition of Layered Perovskite BaLn₂Mn₂O₇

“…The pattern (e) is composed of twinning rotatied by 90 degr ees, and i t indicates t hat t he equi valence bet ween a-a nd b-axis br oke down. T he high-temperature phas e is as umded to be monocl inic s tructure, as s een in annealing s pecimen of BaTb 2 Mn 2 O 7 [7]. In t his exper iment, we s ucceeded t o record t he s tructural change of BaGd 2 Mn 2 O 7 by a video system.…”