Structural and multiferroic properties of trilayer green magnetoelectric Co0.8Ni0.2Fe2O4/K0.25Na0.75Nb0.3/Co0.8Ni0.2Fe2O4 composite structure

We have investigated the structural, dielectric, magnetic-magnetostrictive, ferroelectric-piezoelectric and magnetoelectric (ME) properties of green (Pb-free) Co0.8Ni0.2Fe2O4/K0.25Na0.75NbO3/Co0.8Ni0.2Fe2O4 (CNFO/KNN/ CNFO) trilayer laminate (2-2) multiferroic composite structure. Magnetostrictive Co0.8Ni0.2Fe2O4 phase was synthesized by the solution combustion technique and the piezoelectric K0.25Na0.75NbO3 phase was synthesized by a solid-state method. The trilayer ME laminate composite structure of CNFO-KNN phases fabricated by silver epoxy adhesive bonding technique. The magnetostrictive Co0.8Ni0.2Fe2O4 phase exhibits a piezomagnetic coefficient of - 0.029 ppm/Oe at 1500 Oe magnetic field. The piezoelectric K0.25Na0.75NbO3 showed a piezoelectric charge coefficient of d(33 )similar to 57 pC/N. The trilayer CNFO/KNN/CNFO laminate structure reveals the ME coefficient (alpha(ME)) of 3.06 mV/Oe.cm which is relatively higher than the 0-3 connectivity composite structures. Here, we have discussed the fabrication technique for multiferroic laminate structures for the green magnetoelectric device having alpha(ME) similar to 3.06 mV/Oe.cm with their magnetic/magnetostrictive and ferroelectric/piezoelectric properties.