Growth of c-axis in-plane YBa2Cu4O8 thin films through in situ annealing of precursors deposited by hybrid plasma sputtering

Processing for the growth of YBa2Cu4O8 (Y124) thin films has been investigated by dc 94.92 MHz hybrid plasma sputtering with in situ annealing. The amorphous precursor is found to be the best candidate for growing pure Y124 phase through in situ annealing. The Raman spectrum confirms the Y124 phase by presenting the modes at 250 and 604 cm−1 related to the double Cu-O chains. X-ray diffraction as well as transmission electron microscopy further show that the films are composed of grain with orthogonal c axes in the film plane.