Control of dielectric properties in bismuth ferrite multiferroic by compacting pressure.

Abstract

Single-phase lanthanum-modiŸed bismuth ferrite multiferroic ceramics have been synthesized by the rapid liquid-phase sintering (RLS) method. Phase composition, crystal structure, microstructure and dielectric prop- erties of the Bi0⋅9La0⋅1FeO3 multiferroic have been studied using TG/DTA, XRD, SEM, capacitive and composite dielectric resonator methods. It has been established that the optimal conditions for formation of a perovskite Bi0⋅9La0⋅1FeO3 structure are 850 ◦C after 5 min in air. It has been found that the compacting pressure of the initial mixture of precursors from 90 to 1090 MPa can change the dielectric constant by ~25% in the low-frequency range and by ~80% in the microwave range up to complete elimination of the elastic polarization mecha- nism. The use of the RLS method under various compacting pressures opens additional possibilities for creating multifunctional multiferroics with controlled magnetoelectric coupling.