Orbital domain dynamics in a doped manganite
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چکیده
We explore a number of novel effects near the orbital-order phase transition in a half-doped manganite, Pr0.5Ca0.5MnO3. To probe the unusual short-range orbital order in this system, we have performed coherent soft x-ray resonant scattering measurements in a Bragg geometry to measure dynamics. Near the transition temperature, we observe a small fluctuating component in the scattered signal that is correlated with three effects: a rapidly decreasing total signal and orbital domain size, as well as an abrupt onset of a broad background intensity that we attribute to the thermal production of correlated polarons. Our speckle results suggest that the transition is characterized by a competition between a pinned orbital domain topology that remains static and mobile domain boundaries that exhibit slow, temporal fluctuations. 6 Present address: Department of Physics, La Trobe University, Victoria 3086, Australia 7 Present address: LNCMP, 143 Avenue de Rangueil, 31400 Toulouse, France 8 Author to whom any correspondence should be addressed. New Journal of Physics 10 (2008) 053023 1367-2630/08/053023+12$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
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تاریخ انتشار 2008