The Effect of Mechanical Activation on the Synthesis and Properties of Multiferroic Lead Iron Niobate
The present work studies the effect of high-energy mechanical activation using the planetary-centrifugal ball mill AGO-2 and subsequent annealing on the synthesis and magnetic properties of PbFe0.5Nb0.5O3 (PFN). This technique enables one to perform the mechanically activated synthesis of PFN at much shorter time. The results of X-ray phase analysis, electron microscopic studies and transmission Mossbauer 57Fe spectra measurement are presented and discussed. Mossbauer studies show that the temperature of magnetic phase transition in PbFe0.5Nb0.5O3 powders can be changed by mechanical activation and subsequent annealing.
Dielectric Properties of Undoped and Li-doped Pb(Fe1/2Nb1/2)O3 Ceramics Sintered from Mechanochemically Synthesized Powders
Optimal sintering temperature of PbFe1/2Nb1/2O3 (PFN) ceramics is 1120–1150°C, but ceramics sintered in this temperature range have low resistivity and high losses. Mechanochemical synthesis allows one to lower the optimal sintering temperature of PFN ceramics down to 1000°C, however dielectric losses remain high and the permittivity exhibits large frequency dispersion. In the present work it has been found that similar to the case of the routine solid state synthesis, Li doping enables one to reduce dramatically the losses of the PFN ceramics obtained by sintering the mechanochemically synthesized powders.
Dependences of the dielectric and pyroelectric properties of (1 − x)PbFe1/2Nb1/2O3−xPbTiO3 ferroelectric ceramics solid solutions on the PbTiO3 content in a compositional range of 0 ≤ x ≤ 0.08
Abstract(1 − x)PbFe1/2Nb1/2O3−xPbTiO3 (PFN-xPT) ferroelectric ceramics with low dielectric loss and pronounced anomalies of dielectric and pyroelectric properties near the ferroelectric-ferroelectric phase transition was obtained by doping with lithium. The temperature dependence of the position of the morphotropic boundary between the rhombohedral (monoclinic) and tetragonal phases in the x-T phase diagram of the PFN-xPT system was determined for the first time.