An inhomogeneous paramagnetic state of the LaMnO$_{3+\delta}$ nanoceramics prepared by shock-wave loading

The structural (at $T$ = 300 K) and magnetic properties of LaMnO$_{3+\delta}$ nanoceramic materials prepared by shock-wave loading have been investigated in the paramagnetic region. The samples contain a mixture of the orthorhombic and rhombohedral phases in different ratios. The Curie–Weiss law is satisfied in the temperature range $T >$ 440 K $> 2T_C$, and magnetic polarons are generated in the vicinity of defects at temperatures in the range 300 K $< T <$ 440 K. An increase in the concentration of Mn$^{4+}$ ions leads to a decrease in the Curie temperature $T_C$ due to the decrease in the total number of Mn ions, the size effects of small particles, and the long-range elastic stresses.