CHEMICAL SUBSTITUTION EFFECT ON ANTIFERROMAGNETISM IN LA2CU1-XZNXO4

The results of DC magnetization measurements ( M VS T, H) on La2Cu1-xZ nxO4 (0 less than or equal to x less than or equal to 0.13) are report ed. The Neel temperature of the 3d antiferromagnetic order decreases w ith Zn substitution much more rapidly than the percolation model predi ctions. The composition dependence of T-N is in agreement with theoret ical models accounting for the effect of the impurities concentration on the uncorrelated electronic states. A weak ferromagnetic moment, du e to the spin canting in the 2d antiferromagnetically coupled Cu-O pla nes, is observed persisting well above T-N.