Charge ordering and the related structural phase transition in single-crystal (Bi0.24Ca0.76)MnO3

A single crystal of (Bi0.24Ca0.76)MnO3 has been extensively studied using b oth laboratory and synchrotron radiation x-ray scattering. Using x-ray tech niques we can directly observe the formation of charge stripes associated w ith the low-temperature structural phase transition. Weak satellite peaks w ith a modulation wave vector q approximate to(0.24, 0.24, 0) were observed below the transition temperature. These are associated with the charge orde ring of Mn3+ and Mn4+ ions into charge (and spin) stripes within the perovs kite structure. Measurements of the temperature dependence of the intensity and width of the charge-ordering satellites over the temperature range 10- 240 K were also completed. These demonstrate the first-order nature of the structural phase transition that accompanies the formation of charge and sp in ordering. Measurements of the width of the charge-order satellites demon strate that the correlation length of the charge order is long range at all temperatures, and in all directions, below the structural phase transition . [S0163-1829(99)04017-5].