The influence of MgO on the magnetic and magnetostrictive properties of CoFe2O4 nanoparticles synthesized using spent LIBs

Samples of CoFe2O4/MgO(x) (where x is a series concentration of the MgO, x = 0.00, 0.02, 0.04, 0.06, 0.08) are successfully synthesized by a sol-gel auto-combustion technique using spent LIBs as the raw materials. The effects of MgO concentration on the resultant phase purity, particle size, lattice parameter, micro-structure, magnetic and magnetostrictive properties are investigated. There are significant changes with saturation magnetization, magnetostrictive coefficient and strain derivative when mixing MgO powders with different masses. In contrast, the best magnetic and magnetostrictive properties of the nanoparticles occurs when the mass ratio of CoFe2O4:MgO = 1:0.02. The saturation magnetization, magnetostrictive coefficient and the strain derivative of the CoFe2O4/MgO(0.02) nanocomposites are 77.35 emu/g, −118.6 ppm and −2.16 × 10−9 A−1m, respectively. The CoFe2O4/MgO(x) nanocomposites exhibit huge potential for future use in the fields of non-contact sensors and actuators with low-magnetic fields.