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

LEILA MAR¨ªA SALEH MEDINA; GUILLERMO A. JORGE; DIEGO RUBI; NORMA D'ACCORSO; R. MART¨ªN NEGRI

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 byThe dielectric properties of elastomer composites formed by13 dispersions of bismuth ferrite (BiFeO3) multiferroic filler particles in styrene−dispersions of bismuth ferrite (BiFeO3) multiferroic filler particles in styrene−14 butadiene rubber (SBR) were studied. The SBR/BiFeO3 films (10−100 ¦Ìm)butadiene rubber (SBR) were studied. The SBR/BiFeO3 films (10−100 ¦Ìm)15 were prepared in the presence of electric (E) or magnetic fields (H), showingwere prepared in the presence of electric (E) or magnetic fields (H), showing16 remarkable characteristics in comparison with systems obtained in its absence.remarkable characteristics in comparison with systems obtained in its absence.17 The dispersed multiferroic fillers form clusters of much smaller size whenThe dispersed multiferroic fillers form clusters of much smaller size when18 prepared under E or H. The dielectric constant, ¦Å (measured up to 1 MHz),prepared under E or H. The dielectric constant, ¦Å (measured up to 1 MHz),19 increases with BiFeO3 concentration until reaching saturation. The rise of ¦Å wasincreases with BiFeO3 concentration until reaching saturation. The rise of ¦Å was20 obtained at concentrations much lower for samples prepared in the presence of Eobtained at concentrations much lower for samples prepared in the presence of E21 or H than in its absence. Saturation is assigned to connectivity between filleror H than in its absence. Saturation is assigned to connectivity between filler22 clusters at the largest concentrations, increasing leakage currents and limiting theclusters at the largest concentrations, increasing leakage currents and limiting the23 dielectric behavior. The whole dependence of ¦Å with BiFeO3 concentration wasdielectric behavior. The whole dependence of ¦Å with BiFeO3 concentration was24 described using a proposed model. The dc resistivities, ¦Ñ, increase with BiFeO3described using a proposed model. The dc resistivities, ¦Ñ, increase with BiFeO325 concentration but remain high (¦Ñ ¡Ö 10 G¦¸¡¤cm), allowing using the films asconcentration but remain high (¦Ñ ¡Ö 10 G¦¸¡¤cm), allowing using the films as26 capacitors with filter action between 100 kHz and 7 MHz. The films prepared in the presence of H present strong dependence ofcapacitors with filter action between 100 kHz and 7 MHz. The films prepared in the presence of H present strong dependence of27 the ferroelectric response with magnetic fields applied af ter preparation; that is, electromagnetic coupling was observed in thosethe ferroelectric response with magnetic fields applied af ter preparation; that is, electromagnetic coupling was observed in those28 samples.samples.