MAGNETIC PROPERTIES OF CALCIUM DOPED LANTHANUM NICKELITES La<sub>2-x</sub>Ca<sub>x</sub>NiO<sub>4</sub>
Polycrystalline La2_xCaxNiO4 (x= 0, 0,1, 0,2, 0,3, 0,4) have been synthesized by sintering source oxide powders. The magnetic susceptibility (MS) of the materials has been studied in vacuum from LN to room temperature. The paramagnetic course of the MS temperature dependence has been shown for all the compositions and can be described by the Curie - Weis law at 77-180 К and 180-300 K. An antibatic dependence of the crystal lattice MS and paramagnetic center concentration on solid solution composition has been proven. A conclusion has been made on the existence of a phase transition at -180 К during which the Van Flek Ni2+ ions transform to paramagnetic Ni3+ ions (i.e. the Curie - Weis law is observed).