MAGNETIC-PROPERTIES OF LA2CU1-XMXO4 WITH M=ZN AND NI

The temperature (1.8 less-than-or-equal-to T less-than-or-equal-to 400 K) and concentration (0 less-than-or-equal-to x less-than-or-equal-to 0.10) dependence of the magnetization and magnetic susceptibility of La2Cu1-xMxO4 with M = Zn and Ni have been measured. The results are compared with the recent measurements of the concentration (0 less-than-or-equal-to x less-than-or-equal-to 0.10) dependence of the muon spin rotation of La2Cu1-xZnxO4. The antiferromagnetic order present in La2CuO4, which is very sensitive to the introduction of impurities which create mobile holes (such as Sr substitution of the La site), is much less sensitive to impurities which do not create mobile holes in the CuO2 planes. The Neel temperature T(N) is depressed rapidly with Zn doping and the width of the peak in the susceptibility increases with x, and thus the peak becomes leos well defined. The depression of T(N) in Ni-doped La2CuO4 and the increase in the width of the susceptibility peak are less rapid compared to those in the Zn-doped material. We also study the influence of doping on the metamagnetic behavior which is concomitant with the antiferromagnetism in these systems.