Cation nonstochiometry, crystal structure and magnetic properties of $EuХ_{1-х}Mn_{1+x}O_3$

Using X-ray diffraction analysis (XRD) and magnetometry, the features of the formation of the crystal structure and magnetic subsystem in the $EuХ_{1-х}Mn_{1+x}O_3$ solid solution were studied depending on the content of superstoichiometric manganese. Using the XRD method, it was established that an increase in x leads to a significant decrease in the volume of the unit cell, which is explained by the passage of the disproportionation reaction of manganese and the subsequent redistribution of manganese ions of different valences to nonequivalent positions as follows: ($Eu^{3+}{}_{1-x}Mn^{2+}{}_x)(Mn^{3+}{}_{1-x}Mn^{4+}{}_x)O^{2-}{}_3$. The degree of orthorhombic and Jahn-Teller distortion decreases as x increases. Based on the temperature dependences dM/dT, the temperatures of magnetic transformations, high-temperature ($T_1$) and low-temperature ($T_2$), caused by the ordering of manganese ions in the B- and A-sublattices, respectively, were determined. It has been established that an increase in the content of Mn ions reduces the temperature $T_1$. Magnetization measurements carried out in $Eu^{3+}{}_{1-x}Mn^{2+}{}_x)(Mn^{3+}{}_{1-x}Mn^{4+}{}_x)O^{2-}{}_3$ in a low applied magnetic field demonstrate a magnetization reversal at temperatures below $T_1$.