MAGNETIC-PROPERTIES OF EU-DOPED LA2-XSRXCUO4 STUDIED BY ESR

By analyzing electron spin resonance spectra of Gd spin probes in La2- x-yEuySrxCuO4, we find that in the low temperature tetragonal phase th e frequency of the spin fluctuations omega(sf) of Cu ions considerably slows down in the samples with strongly suppressed superconductivity (Sr contents x<0.17), The effect is especially pronounced for x close to 1/8. However, for the samples with Sr concentration x greater than or similar to 0.17 the specific features of the spin dynamics of the l ow temperature structural phase almost vanish, whereas fully developed superconductivity reappears. [S0163-1829(98)50738-2].