Structural Characterization of Strain Relaxed (100)-Oriented Nd$_{0.5}$Sr$_{0.5}$MnO$_3$ Thin Films

Half-doped manganites exhibit intriguing charge ordering (CO) properties. Pseudocubic (110)-oriented thin films can preserve bulk properties and show a charge ordering-ferromagnetic (CO-FM) transition. However, for (100) oriented films grown on traditional perovskite substrates, no CO-FM transition has been reported so far. Here we successfully realized the CO-FM transition in (100)-oriented $\mathrm{Nd_{0.5}Sr_{0.5}MnO_3}$ (NSMO) thin films grown on $\mathrm{SrTiO_3}$ substrates by inserting a perovskite-like flexible buffer layer $\mathrm{Sr_3Al_2O_6}$. From temperature-dependent X-ray elastic scattering, we observed changes in the NSMO lattice constants exactly at the CO-FM transition temperature determined from transport and magnetization measurements. Moreover, we observed CO peaks suggesting a different ordering pattern compared to the bulk or (110)-oriented thin films. These results provide new opportunities to create and study novel electronic ground states unexplored in films grown on the rigid substrates used up to now.