States of atoms and interatomic interactions in complex perovskite-like oxides: XXIII. Magnetic dilution in the La(Sr)NiO<Subscript>3</Subscript>-LaGaO<Subscript>3</Subscript> system

Magnetic susceptibility of dilute solid solutions of lanthanum gallates doped with nickel and also with nickel and strontium was studied. Calculations showed that the main contribution into the exchange interactions in gallates doped with nickel is made by dimers formed by low-spin nickel(III) (J-20 cm^?1), and in gallates doped with strontium and nickel the main contribution is due to dimers formed by high-and low-spin nickel (J 10 cm^?1). Electrical conductivity measurements showed that the samples under study are electron and ion conductors.