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

Abstract

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.