Magnetoelectric properties of lead-free Ni0.93Co0.02Mn0.05Fe1.95O4–Na0.5Bi0.5TiO3 multiferroic composites synthesized by spark plasma sintering

• Ni0.93Co0.02Mn0.05Fe1.95O4–Na0.5Bi0.5TiO3 composites are synthesized by SPS.
• The composites exhibit apparent ferromagnetic and ferroelectric characteristics.
• There is quite a high magnetoelectric coefficient for the 0.5 NCMF−0.5 NBT composite.
• SPS is a promising method of synthesizing multiferroic ceramic composites.

Lead-free multiferroic ceramic composites of x Ni0.93Co0.02Mn0.05Fe1.95O4−(1–x) Na0.5Bi0.5TiO3 (x NCMF−(1–x) NBT, where x=0.1, 0.2, 0.3, 0.4 and 0.5 mol fraction) were synthesized by spark plasma sintering (SPS) in conjunction with high-energy ball milling. The phases, dielectric, piezoelectric, ferroelectric, magnetic and magnetoelectric properties of the composites were analyzed. The composites were composed of a mixture of spinel and perovskite phases. All the composite samples exhibited both apparent ferroelectric and ferromagnetic characteristics as well as considerable magnetoelectric (ME) effects. The maximum value of the ME voltage coefficient of the composites was quite high, being up to ~670 mV cm−1 Oe−1 for the 0.5 NCMF−0.5 NBT composite. Overall, the synthesized composites were promising in terms of electrical, magnetic and magnetoelectric properties, indicating that the SPS is a promising method of fabricating ME composite materials.