Magnetic Properties of the LaNi1–xWxO3(0≤x≤0.25) Perovskites

Abstract

Magnetic properties of the LaNi1−xWxOx(0≤x≤0.25) mixed oxides have been studied from the temperature and magnetic field (H) dependence of the magnetization (M) and low-temperature neutron diffraction experiments. The variation ofMwith temperature shows the presence of weak ferromagnetic interactions with Curie temperatures ranging from 200 to 250 K. These interactions become stronger asxincreases and this fact has been interpreted in relation to the progressive electronic localization that takes place in this perovskite-like system. The observed ferromagnetic behavior is confirmed by the hysteresis loops obtained in theMvsHcurves at different temperatures. The saturation values are however very low in comparison with the expected ones for Ni2+or Ni3+. On the other hand, an extra peak in the neutron diffraction experiments for thex=0.20 phase shows the appearance of an antiferromagnetic ordering, which has been interpreted on the basis of a G-type magnetic mode. Both results can be understood considering antiferromagnetic in character interactions with an important canting of the spin arrangement, giving therefore rise to a weak ferromagnetic component, which has been characterized from magnetization measurements. These results have been summarized in a phase diagram in which the most relevant electronic features of the title system can be visualized.