Towards novel functional properties by interface reaction in mixtures of BaTiO3-Fe2O3 composite ceramics

In the present work, composite ceramics of ferroelectric BaTiO3 with magnetic αFe2O3 were prepared by mixing powders in different ratio. The M(H) loops at room temperature show a “wasp-waisted” character, with multiple components, determined as result of the formation of magnetic phases with contrasting coercivities (hard BaFe12O19 and soft Ba12Ti28Fe15O84 phases) in different ratios, according to the X-ray diffraction patterns. The extrinsic contributions play important roles in modifying the electrical properties in the ceramics with large amount of magnetic phases, causing space charge effect and Maxwell-Wagner relaxations. The high field properties of composite ceramics show non-hysteretic nonlinearity for all investigated ceramics, together with a reduction of zero field permittivity with increasing magnetic amount, making from these composites possible tunable materials interesting for applications.