NMR OF HIGH T-C SUPERCONDUCTORS

Results of our NMR measurements of high T-c superconductors are review ed. From systematic measurements of NQR frequency, Knight shift, nucle ar spin lattice relaxation rate and nuclear transverse relaxation rate over a wide hole concentration range from light to heavy doped compou nds together with the impurity and pressure effect, following results are concluded. The numbers of the holes at the respective sites of Cu and O site in the CuO2 plane govern the several physical properties of the system. There are optimum values of these hole numbers to produce highest T-c. The superconducting properties are well explained consis tently by the d-wave pairing model. T-c is found to be correlated inti mately with the antiferromagnetic spin fluctuation parameters that gov erns the nuclear relaxation. The mechanism for the superconductivity i s magnetic in origin.