SBR/BiFeO3 Elastomer Capacitor Films Prepared under Magnetic and Electric Fields Displaying Magnetoelectric Coupling

SALEH MEDINA, L.M.; G. A. JORGE; RUBI, D.; D´ACORSSO, N.; NEGRI RICARDO MARTÍN

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 119 p. 23319 - 23328

1932-7447

ABSTRACT: The dielectric properties of elastomer composites formed bydispersions of bismuth ferrite (BiFeO3) multiferroic filler particles in styrene−butadiene rubber (SBR) were studied. The SBR/BiFeO3 films (10−100 μm)were prepared in the presence of electric (E) or magnetic fields (H), showingremarkable characteristics in comparison with systems obtained in its absence.The dispersed multiferroic fillers form clusters of much smaller size whenprepared under E or H. The dielectric constant, ε (measured up to 1 MHz),increases with BiFeO3 concentration until reaching saturation. The rise of ε wasobtained at concentrations much lower for samples prepared in the presence of Eor H than in its absence. Saturation is assigned to connectivity between fillerclusters at the largest concentrations, increasing leakage currents and limiting thedielectric behavior. The whole dependence of ε with BiFeO3 concentration wasdescribed using a proposed model. The dc resistivities, ρ, increase with BiFeO3concentration but remain high (ρ ≈ 10 GΩ·cm), allowing using the films ascapacitors with filter action between 100 kHz and 7 MHz. The films prepared in the presence of H present strong dependence ofthe ferroelectric response with magnetic fields applied af ter preparation; that is, electromagnetic coupling was observed in thosesamples