Magnetoelectric films using multiferroic compounds including elastomeric matrixes

L. SALEH MEDINA; D. RUBI; G. JORGE; M.NEGRI

Conferencia; 6th International Conference on Science and Technology of Composite Materials; 2015

The magnetoelectric effect allows the modulation of electric properties by magnetic fields and vice versa. This effect can be achieved by intrinsic multiferroic materials (which contains simultaneously two or more ferroic orders) or by superposition of ferroelectric and ferro(ferri)magnetic inorganic compounds. In this work, these types of compounds were synthetized and deposited on different substrates: i) n-Si by pulsed laser deposition (PLD) and ii) introduced into elastomeric styrene-butadiene rubber (SBR) to obtain a flexible and functional composite.Different compounds, (Bi1-xYx)FeO3, CoFe2O4 and Fe3O4, were synthetized by acid-base co-precipitation and characterized by XRD, EDS, SEM, FTIR, TEM, DSC, Mössbauer Spectroscopy and Impedance Spectroscopy. Magnetic properties were determined in a Vibrating Sample Magnetometer while the electric characterization was performed on a Precision LC Material Analyzer (Radiant Technologies). Commercial BaTiO3 was also used. Films prepared by PLD were obtained using compacted disks of the inorganic compounds as targets and experimental conditions were adjusted to optimize the quality of the films. On the other hand, elastomeric composites were prepared by adding the materials to a solution of commercial styrene-butadiene rubber in toluene. The solvent was partially evaporated and then the viscous suspension was deposited by spin coating onto ITO glass or silicon wafers (SBR films). SBR films were dried under the application of magnetic or electric fields in order to align the particles in the polymer matrix.In both cases (PLD and SBR films) the electrical frequency response were modelled with a R//C model. The systems display ferroelectric loops (P-E curves) at room temperature. The P-E curves were measured at different magnetic fields and both the coercive field (Hc) and the remanent polarization (Pr) change with the magnetic field.PLD films show higher values of electric polarization but also higher leakage currents than SBR films. At present, multiferroic capacitors are designed using these materials.