Magnetic susceptibility investigations of the La2NiO4+δ system

Magnetic susceptibility studies were performed on La2NiO4+δ in the temperature range between 300 Κ and 1100 Κ as a function of composition, δ. Samples with nearly ideal stoichiometric ratios (δ = .002) show a previously unreported transition to antigferromagnetic order which occurs in the same temperature range as the semiconductor-metal transition. An increase in δ leads to a suppression of the magnetic ordering temperature while the transition in resistivity remains unaltered. This result is interpreted in terms of an oxygen interstitial defect mechanism and the quasi-two-dimensional structure of the material