MAGNETIC PHASE-DIAGRAM OF LIGHTLY DOPED LA2-XSRXCUO4 FROM LA-139 NUCLEAR-QUADRUPOLE RESONANCE

The magnetic phase diagram of La2-xSrxCuO4 in the antiferromagnetic re gime (x less-than-or-equal-to 0.02) has been derived from La-139 nucle ar quadrupole resonance studies from 4 to 250 K. The data demonstrate freezing of the doped holes' effective spin degrees of freedom below T (f) almost-equal-to (815 K)x into a spin-glass-like state which is sup erimposed on the antiferromagnetic background. These and previous resu lts allow a detailed magnetic phase diagram to be constructed for x le ss-than-or-equal-to 0.05 and reveal a distinct crossover at x almost-e qual-to 0.02 in the nature of the spin-glass transition.