Copper Oxide High-temperature Superconductors, Superconductivity, Magnetic Properties

This thesis mainly focuses on the magnetic and conductive behaviors of double-doped La_1.85-2xSr_0.15+2xCu_1-xRu_xO4, the effect of magnetic ion Ru on LSCO system is researched, the experiment came out with some interesting results. The relevant content has been published in overseas magazine.This thesis is divided into two chapters.Chapter IGiven a brief overview of the history, process, current status, and prospect in application of high-temperature superconductor, and purposely summed up the La series high-temperature superconductor's history in research. In detail, the crystal structure, electronic structure, the superconductivity, the magnetic properties and the transport properties of copper oxide superconductors are discussed. Also we give a brief review on the explanation of the mechanism of high-temperature superconductivity.Chapter IIThe effect of Ru on LSCO system was studied. The serial samples were obtained successfully due to double-doping method. The doping concentration is up to x=0. 30, we found that the suppression in this system can not be ascribe to the traditional magnetic pair-breaking theory, but to the localization of the carriers brought about by Ru doping. Through the measurement of magnetization , we found there is transition from spin-glass, cluster-spin state and AFM state.