INFLUENCE OF OXYGEN STOICHIOMETRY ON THE ANTIFERROMAGNETIC ORDERING OF SINGLE-CRYSTALS OF LA2NIO4+DELTA

We report here on magnetic measurements of well-characterized single crystals of La2NiO4+delta, for H both parallel and perpendicular to the c axis, and for compositions in the range 0 < delta < 0.067. The antiferromagnetic ordering temperature is shown to be very sensitive to the oxygen stoichiometry parameter-delta. A discontinuity in the delta-dependence of the Neel temperature has been observed and is attributed to a change in the structure. For 0.055 less-than-or-equal-to delta less-than-or-equal-to 0.067 we report a time dependence of the remanent magnetization in the basal plane, which suggests that an anisotropic spin-glass phase exists over a narrow composition range in this system.