We have successfully grown epitaxial CoFe ₂ O ₄ (CFO) thin film on SrTiO ₃ by metal organic chemical vapor deposition. In order to understand the surface structure and its correlation with magnetic properties, CFO thin films were deposited at a range of deposition temperatures. As the deposition temperature is decreased, a huge effect on film morphology and surface roughness is observed, resulting from a change in the size and density of the crystal nuclei. These changes to grain structure and surface roughness modify the energy landscape of the films and are major contributors to the change in magnetic properties as a function of deposition temperature: the direction of the easy axis is aligned in-plane at lower deposition temperatures and lower anisotropy between different directions is observed in the rough films grown at high temperature.