  An electronic effect on a macroscopic domain structure is found in a strongly
correlated half-doped manganite film Nd$_{0.5}$Sr$_{0.5}$MnO3 grown on a (011)
surface of SrTiO3. The sample has a high-temperature (HT) phase free from
distortion above 180K and two low-temperature (LT) phases with a large
shear-mode strain and a concomitant twin structure. One LT phase has a large
itinerancy (A-type), and the other has a small itinerancy (CE-type), while the
lattice distortions they cause are almost equal. Our x ray diffraction
measurement shows that the domain size of the LT phase made by the HT-CE
transition is much smaller than that by the HT-A transition, indicating that
the difference in domain size is caused by the electronic states of the LT
phases.
