Direct evidence for the suppression of charge stripes in epitaxial La$_{5/3}$Sr$_{1/3}$NiO$_4$ thin films

We have successfully grown epitaxial La$_{5/3}$Sr$_{1/3}$NiO$_4$ films with a small crystalline mosaic using pulsed laser deposition. With synchrotron radiation, the x-ray diffraction peaks associated with charge stripes have been successfully observed for relatively thick films. Anomalies due to the charge-ordering transition have been examined using four-point probe resistivity measurement. We also have produced multilayer films with the same total thickness through the use of thin films La$_{5/3}$Sr$_{1/3}$NiO$_4$ alternating with SrTiO$_3$. A thorough search for the charge stripe peaks in the multilayers has been negative; the stripes appear to be suppressed for epitaxial thin films. This suggests that electron-lattice interactions are critical for the formation of stripe phases.