Effect of CoFe2O4 weight fraction on multiferroic and magnetoelectric properties of (1 − x)Ba0.85Ca0.15Zr0.1Ti0.9O3 − xCoFe2O4 particulate composites

Abstract

Different compositions of the composite lead-free multiferroic magnetoelectric systems are fabricated by employing piezoelectric Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) and magnetostrictive CoFe2O4 (CFO) by varying the CFO weight fraction. The magnetic, dielectric, ferroelectric and magnetoelectric (ME) properties of the system are analyzed and found to be varying with the ferrite concentration. Even though the composite systems exhibit high magnetocapacitance (MC) properties (~ 35%), the possible stray contributions from magnetoresistance and magnetostriction make it unreliable for the quantitative determination of ME coupling coefficient (MECC). Therefore, a dynamic method is chosen for the measurement of magnetoelectric coupling. All the compositions have shown fairly good ME coupling. It is found that the ME coupling increases with ferrite fraction and the highest ME coupling of 14.8 mV/(cm Oe) is observed for 0.6BCZT–0.4CFO composite. It is also observed that the ME voltage increases linearly with the ac modulating field with a voltage generation of 1.25 V/cm (for x = 0.4) for a small ac modulating field of 100 Oe. This high sensitivity and linear response of ME coupling to the ac magnetic fields offer the possibility of employing these particulate composites for a wide range of applications from magnetic field sensors to energy harvesters.