High temperature superconductors and the insulating parent compounds

Summary form only given. The introduction of charge carriers to some oxides has been observed to lead to superconductivity, even though their transition temperatures (T_c) are generally low. The recently discovered high-T_c oxide compounds apparently exhibit similar characteristics, i.e., for each high-T_c compound system, there exists an insulating parent compound. Study of the occurrence and correlation of these superconducting and insulating phases will not only shed light on the understanding of this unusual high-temperature superconductivity, but will also provide insight into device applications of this new class of materials. A systematic investigation has been carried out on some of the superconducting compounds as well as their insulating parent compounds. Important information has been obtained about the occurrence of superconductivity, the correlation of superconductivity with magnetism, the dimensionality of superconductivity, the formation of a superconducting homologous phase, etc.