Regularities and Mechanisms of Composition Influence on Magnetic and Nonlinear Electrical Characteristics of La–Sr Manganites with Combined Substitution for Manganese

The data are shown on magnetic properties and peculiarities of nonlinear current-voltage characteristics of manganites with substitution of ( $${\text{Fe}}_{{{\text{0}}{\text{.5}}}}^{{{\text{3 + }}}}{\text{Sc}}_{{{\text{0}}{\text{.5}}}}^{{{\text{3 + }}}}$$ ), ( $${\text{Ni}}_{{0.5}}^{{2 + }}{\text{Ge}}_{{0.5}}^{{4 + }}$$ ), ( $${\text{Zn}}_{{0.5}}^{{2 + }}{\text{Ge}}_{{0.5}}^{{4 + }}$$ ), ( $${\text{Mg}}_{{{\text{0}}{\text{.5}}}}^{{{\text{2 + }}}}{\text{Ge}}_{{{\text{0}}{\text{.5}}}}^{{{\text{4 + }}}}$$ ) ions pairs for manganese in La–Sr system. The samples containing (Fe,Sc), (Ni,Ge) and (Zn,Ge) have S-shaped sections of negative differential resistance, and (Mg,Ge)-substituted manganite exhibits the property of voltage stabilization.