Nanoscale Anisotropic structural Correlations in the Paramagnetic and Ferromagnetic Phases of Nd sub (0.5) Sr sub (0.5) MnO sub 3

We report synchrotron x-ray scattering studies of short-range structural correlations and diffuse scattering in Nd sub (0.5) Sr sub (0.5) MnO sub 3. Highly anisotropic structural correlations were found in both the paramagnetic and ferromagnetic states of this compound. The corresponding correlation length grows with decreasing temperature and reaches its maximum at the charge-ordering transition temperatue; below this temperature, these structural correlations abrutly disappear. Single-polaron diffuse scattering, while reduced, is clearly present in the ferromagnetic state suggesting that sub-stantial local lattice distortions are present in this phase. We argue that our measurements indicate that nanoscale regions exhibiting layered magnetic and orbital order exist in the paramagnetic and ferromagnetic phases in Nd sub (0.5) Sr sub (0.5) MnO sub 3.