Charge/orbital ordering structure of Pr1-xCaxMnO3 (x=3/8) examined by low-temperature transmission electron microscopy -: art. no. 097201

The structural phase transition of Pr1-xCaxMnO3 (x = 3/8) was investigated by means of low-temperature transmission electron microscopy. Superlattice reflection spots with a modulation wave vector q(1) = (0, 1/2, 0) appeared below 230 K, indicating formation of the d(3x2-r2)/d(3y2-r2) type of charge/orbital ordering. Below 150 K, a new series of superlattice reflection spots with a modulation wave vector q(2) = (1/4, 1/4, 1/2) appeared, suggesting an additional ordering of excess 1/8 Mn3+, necessary due to the deviation of x from 1/2, with the occupation of the d(3z2-r2) type of e(g) orbital.