Structure, the grain structure, and the dielectric properties of ceramics of solid solutions YCu$_{x}$Mn$_{1-x}$O$_{3}$

Solid solution ceramics of the YCu$_{x}$Mn$_{1-x}$O$_{3}$ system at $x$ = 0.05; 0.10; 0.15 were prepared by solid-phase reactions followed by sintering using conventional ceramic technology. The study of their structure, microstructure and dielectric properties including of temperature and frequencies investigation of dielectric permittivity, conductivity and tangent of dielectric loses is carried out. It is established that hexagonal phase is predominantly formed in the ceramics. Its grain structure is unhomogenius, while synthesis is performed with the formation of liquid phases of eutectic origin. It is shown that anomalous behavior of dielectric characteristics at $T$ = 30–200$^\circ$С connected to interlayer polarization effects, while features at $T$ = 222$^\circ$С ($x$ = 0.05), 234$^\circ$С ($x$ = 0.10) and 247$^\circ$С ($x$ = 0.15) we connected to “isostructural” phase transition that is intermediate between the ferroelectric and paraelectric phases.