Critical factor for epitaxial growth of cobalt-doped BaFe₂As₂ films by pulsed laser deposition

We heteroepitaxially grew cobalt-doped BaFe₂As₂ films on (La,Sr)(Al,Ta)O₃ single-crystal substrates by pulsed laser deposition using four different wavelengths and investigated how the excitation wavelength and pulse energy affected growth. Using the tilting and twisting angles of X-ray diffraction rocking curves, we quantitatively analyzed the crystallinity of each film. We found that the optimal deposition rate, which could be tuned by pulse energy, was independent of laser wavelength. The high-quality film grown at the optimal pulse energy (i.e., the optimum deposition rate) exhibited high critical current density over 1 MA/cm² irrespective of the laser wavelength.