Phase diagram of the system of (1–х)BiFeO3–xPbFe0.5Nb0.5O3 solid solutions at room temperature

Resumo

Experimental samples of solid solutions of the (1–x)BiFeO_3–xPbFe_0.5Nb_0.5O₃ (0.00 ≤ x ≤ 1.00, Δx = 0.025–0.05) system have been prepared according to the conventional ceramic technology. Their structural and dielectric characteristics have been studied. A phase diagram of the system at room temperature has been plotted taking into account the crystallochemical specificity, spatial inhomogeneity, and structural imperfection of the samples. This diagram is characterized by the presence of solid substitutional and interstitial solutions; the formation of concentration ranges with a dominant role of BiFeO₃ and PbFe_0.5Nb_0.5O₃; the presence of five single-phase regions, two regions of coexistence of phase states, and three morphotropic regions; and the formation of six regions with a constant experimental unit-cell volume. Correlations between the structural characteristics and dielectric properties of the ceramics under study have been established.