Laminated composites with connectivity 2–2 (L–B) have been fabricated from of two methods: solid state reaction and Pechini.
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The influence of grain size and interfacial interdiffusion upon the dielectric, magnetic and magnetoelectric properties is observed.
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The as a function of the DC bias magnetic field (Happl) was measured under longitudinal () and transverse () conditions.
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The composite shows a magnetoelectric effect in room temperature.
Abstract
We report on specific features of the dielectric and magnetic properties as well as magnetoelectric coupling coefficients of the La0.7Ba0.3MnO3 (L)-BaTiO3 (B) 2–2 type ceramic composite. The powder of L and B was synthesized by two different methods (solid state reaction and Pechini). Orthorhombic and tetragonal phases were observed for the separated phases L and B of the composite, respectively, for both synthesis methods. The characteristics of grain size and interfacial interdiffusion in the L–B–L composite obtained for different synthesis method were studied, showing that diffusion was a typically physical migration, which can be mainly controlled by the grain size. Anomalies in the observed dielectric behavior are attributed to the internal residual stresses and chemically inhomogeneous regions. The existence of a broad magnetic transition observed in the pure L phase and laminated L–B–L composite was also attributed to its small grain size. A comparison of the maximum transversal and longitudinal ME coupling coefficients, at room temperature, is also shown.