The 130 K transition in Bi oxides heavily doped by iron phthalocyanine. Superconductivity versus magnetism

The observation and detailed investigation of the highly reproducible transition with onset at 130 K are reported in samples of Bi oxides (both 2212 and 2223 systems) doped with iron phthalocyanine, involving effects of temperature, magnetic field, and chemical composition on dc magnetization and microwave absorption spectra of the samples. The experimental magnetic data are suggestive of a superconducting nature of the transition; however, no reliable electrical resistivity drop is observed at 130 K to confirm the occurrence of superconductivity. (orig.)