Interplay between Charge, Orbital, and Magnetic Order in Pr{sub 1-x}Ca{sub x}MnO{sub 3}

We report resonant x-ray scattering studies of charge and orbital order in Pr{sub 1-x}Ca {sub x}MnO{sub 3} with x=0.4 and 0.5. Below the ordering temperature, T{sub O}=245 K , the charge and orbital order intensities follow the same temperature dependence, including an increase at the antiferromagnetic ordering temperature, T{sub N} . High resolution measurements reveal, however, that long range orbital order is never achieved. Rather, an orbital domain state is formed. Above T{sub O} , the charge order fluctuations are more highly correlated than the orbital fluctuations. We conclude that the charge order drives the orbital order at the transition. (c) 1999 The American Physical Society.