MAGNETIC-PROPERTIES OF ND2-XSRXNIO4+DELTA OXIDES

The system Nd2-XSrXNiO4+delta presents a rich variety and complex magn etic behavior depending on the Sr content and the oxygen stoichiometry . All the prepared samples were characterized by X-ray diffraction and the stoichiometry was carefully determined by thermogravimetric metho ds. We concentrate in a doping range from 0.2<X<0.8, and two set of sa mples, first as-grown (delta greater than or equal to 0), and second r educed (delta<0). The reduced samples present a weak maximum at high t emperature (T-N1=330K) related to the antiferromagnetic ordering of th e Ni sublattice. At low temperature there is also a maximum (5K<T-N2<1 7K) depending on the Sr content. The as-grown samples are characterize d by a maximum in the magnetic susceptibility at low temperatures (T(m ax)approximate to 13-16K), and a clear departure from the linear Curie -Weiss behavior at much higher temperatures.