Enhanced ferroelectric and ferromagnetic properties of xNiFe2O4/(1–x)Ba0.94Ca0.06Ti0.975Zr0.025O3 nanocomposites

Abstract

Bi-phase multiferroic composites of NiFe2O4/Ba0.94Ca0.06Ti0.975Zr0.025O3 (BCTZ/NFO) were successfully fabricated by high-energy ball milling combined with heat treatment. X-ray diffraction patterns and Raman spectra confirmed the successful coexistence of BCTZ and NFO phases in the final composites, which had an average particle size of 50 nm. However, the number of large particles increased with the increased NFO concentration in the composites. Optical properties of the composites were also modified by the NFO content, where the absorption band tended to the visible region and band-gap energies (E g) decreased with the increase of NFO. Ferromagnetic and ferroelectric properties of the BCTZ/NFO composites were also tuned by NFO additive content. Both saturation magnetisation (M s) and remnant magnetisation (M r) increased with the increase of NFO content, where the maximum values of M s = 22.52 emu g−1 and M r = 1.48 emu g−1 for composites with 40% NFO concentration, while coercivity (H c) was maintained at about 60 Oe. Maximum polarisation (P max), remnant polarisation (P r), and coercive field (E c) values all increased with NFO concentration, with 10% NFO providing the highest P max (= 0.249 μC cm−2) and P r (= 0.116 μC cm−2) values, and 30% NFO providing the highest E c (= 1.720 kV cm−1) value with a maximum applied voltage of 1 kV. Therefore, the multiferroic properties of BCTZ/NFO composites could be enhanced with an appropriate concentration of NFO, which led to a wide range of practical applications in the advanced electronic device field.