Operational characteristics of an high temperature superconducting (“HTS”) film comprised of an HTS material may be improved by depositing a modifying material onto appropriate surfaces of the HTS film to create a modified HTS film. In some implementations of the invention, the HTS film may be in the form of a “c-film.” In some implementations of the invention, the HTS film may be in the form of an “a-b film,” an “a-film” or a “b-film.” The modified HTS film has improved operational characteristics over the HTS film alone or without the modifying material. Such operational characteristics may include operating in a superconducting state at increased temperatures, carrying additional electrical charge, operating with improved magnetic properties, operating with improved mechanic properties or other improved operational characteristics. In some implementations of the invention, the HTS material is a mixed-valence copper-oxide perovskite, such as, but not limited to YBCO. In some implementations of the invention, the modifying material is a conductive material that bonds easily to oxygen, such as, but not limited to, chromium.