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In this work, the structural phase state and physical properties of YbMn1-xFexO3 (hereinafter YbMF) ceramics in the range of x = 0.0–1.0 with a concentration step Δx = 0.1 were studied by complex methods. X-ray diffraction revealed that the YbMF compositions in the range of x = 0.1–0.5 were hexagonal (H) phase solid solutions. In the concentration range of x = 0.6–0.8, the hexagonal and orthorhombic (O) systems coexist, and the unit cell parameters of these phases rise with increasing x. The study of the lattice parameters, bond lengths, bond angles and the main parameters of the magnetic hysteresis loop of the H-phase revealed the presence of a singular point x = 0.5 in the concentration range, where extrema of the corresponding parameters were observed. By analyzing the Cole–Cole plots for the electric modulus M*(ω), a conclusion was drawn about the thermally activated nature of the dielectric relaxation for each composition with a single relaxation time τ. The magnetodielectric MD(ω) and magnetoresistive MR(ω) coefficients measured in crossed and parallel fields E and H show high values, which reach 1.6% and 50%, respectively, depending on the frequency of the measuring field. [ABSTRACT FROM AUTHOR]

In this work, the structure and physical properties of (1 − x)(CoFe2O4) − x(PbTiO3) compositions, synthesized by the solid-phase method, were studied for the first time using complex methods. It was found that the solid-phase sintering of the inverse spinel CoFe2O4 (CFO) and the ferroelectric PbTiO3 (PTO) is frequently accompanied by the formation of additional phases—hexaferrite PbFe12O19 (PFO) and solid solutions, which were identified by X-ray diffraction, energy-dispersive X-ray analysis, and Raman spectroscopy. The dependencies of the unit cell parameters of the main components and additional phases on the concentration of PTO were studied at room temperature. The concentration interval (x = 0.3–0.7) with extreme values of structural parameters and non-monotonic changes of the physical properties was discovered. Complex quantities such as dielectric permittivity ɛ*(ω) and electric modulus M*(ω) were studied over a wide range of frequencies and temperatures using dielectric spectroscopy. The polarization switching kinetics of (1 − x)(CFO) − x(PTO) compositions were studied, and the saturated ferroelectric hysteresis loops P(E) with maximum spontaneous polarization Ps equal to 132 μC/cm2 were obtained for the first time. The bandgap Eg was determined by optical absorption spectroscopy at room temperature; Eg varies depending on the PTO concentration in the range 2.11–2.57 eV. The dynamic properties of the compositions were studied by Fourier transform infrared spectrometer (FTIR) and Raman spectroscopy. The Raman modes corresponding to PFO are well detected starting from compositions 0.3(CFO)–0.7(PTO). [ABSTRACT FROM AUTHOR]