Magnetic ordering and instability investigation of multiferroic Pb(Fe2/3W1/3)O3 ceramics by microwave dielectric spectroscopy

The microwave dielectric and magnetic properties of Pb(Fe2/3W1/3)O3 multiferroic ceramics were investigated. A dielectric dispersion occurring in the frequency range 100 MHz–3 GHz and in a broad temperature range showed itself to be a powerful tool to detect magnetostrictive effects. The experimental results revealed the following remarkable features: the temperature dependence of fRfR (characteristic frequency) and the dielectric strength ΔεΔε (characteristic of the dispersion) enabled us to identify not only the para–ferroelectric (TC≈180TC≈180 K) but also the para–antiferromagnetic (TN≈340TN≈340 K) phase transitions, while magnetic measurements revealed the para–antiferromagnetic ordering and a weak superexchange interaction (TN2∼15TN2∼15 K). Additionally, both characterizations confirmed the existence of structural or magnetic instabilities around 250 K.

► Dense multiferroic lead iron tungstate prepared by B-site precursor method.
► Dielectric proprieties measured at microwaves frequencies at Neél temperature.
► Spin–lattice coupling occurring at the magnetic transition.
► Existence of structural and magnetic instabilities around 250 K.