Negative magnetostrictive paper formed by dispersing CoFe₂O₄ particles in cellulose nanofibrils

Polymers are often combined with magnetostrictive materials to enhance their toughness. This study reports a cellulose nanofibril (CNF)-based composite paper containing dispersed CoFe₂O₄ particles (CNF-CoFe₂O₄). Besides imparting magnetization and magnetostriction, the incorporation of CoFe₂O₄ particles decreased the ultimate tensile strength and increased the fracture elongation of the CNF-CoFe₂O₄ composite paper. CNF was responsible for the tensile properties of CNF-CoFe₂O₄ composite paper. Consequently, the magnetic and magnetostrictive properties and tensile properties of CNF-CoFe₂O₄ composite paper can be controlled by changing the mixture ratio of CNF and CoFe₂O₄ particles.