HOLE-DOPING EFFECT ON THE SPIN-STATE AND MICROSCOPIC MAGNETIC-PROPERTIES OF LA1-XSRXCOO3 (0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5) - CO-59 AND LA-139 NMR MEASUREMENTS

Co-59 and La-139 NMR measurements have been made to reveal microscopically the hole-doping effect on the spin state and magnetic properties of La1-xSrxCoO3 (0 less than or equal to x less than or equal to 0.5). The signal from the Co atoms with no Sr nearest neighbors was observed in the spin-glass region below x(c) similar to 0.18. From the analysis of the temperature dependence of the Knight shift, the ground state of such Co atoms was found to be the trivalent low-spin state (1)A(lg). Above x(c), we observed at 4.2 K the Co-59 and La-139 signals which come from the cluster-glass region with a finite ferromagnetic correlation. Thus, it was microscopically confirmed that the boundary between the two regions is located at x(c) similar to 0.18.