Oxygen Doping Study of Cuprate/Manganite Thin-Film Heterostructures*

Recent studies of thin-film heterostructures comprising superconducting cuprates and ferromagnetic manganites have revealed a range of novel physical phenomena [1].~ These phenomena are believed to involve complex interfacial interactions between competing order parameters [2], and appear to be highly sensitive to the doping of carriers [3]. To further examine these phenomena, we carry out a systematic oxygen-doping study of YBa$_{2}$Cu$_{3}$O$_{6+x}$/La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ multilayers, grown epitaxially by pulsed laser-ablated deposition. Our samples are characterized by electrical transport and magnetization measurements, as well as x-ray diffraction and various scanning microscopy probes.~ To assess the role of interfacial magnetism on the cuprate layer, YBa$_{2}$Cu$_{3}$O$_{6+x}$ /LaNiO$_{3}$ samples are also made and measured as a comparison.~ We also examine the effects of cation substitution in the YBa$_{2}$Cu$_{3}$O$_{6+x}$ layer, in order to determine the extent of carrier doping across the~interface.~ [1] for example, see Z. Sefrioui et al., Phys. Rev. B 67, 214511 [2] J. Hoppler et al., Nature Materials 8, 315 [3] V. Pe\~{n}a et al., Phys. Rev. Lett. 97, 177005