Enhanced Strain Sensitivity to Magnetic Field in Magnetostrictive Cu–Co Ferrites via Partial Substitution with Various Trivalent Ions

The magnetostrictive properties of Cu0.5Co0.5Fe2.0O4 were controlled via partial substitution with various trivalent ions. A single-phase cubic spinel structure was successfully obtained for the Cu0.5Co0.5X0.1Fe1.9O4 (X = Al, Cr, Mn, Ga, and In) samples, indicating that Fe3+ ions in Cu0.5Co0.5Fe2.0O4 can be partially substituted by Al3+, Cr3+, Mn3+, Ga3+, and In3+ ions. In the magnetic field dependence of the strain, the significant enhancement in magnetic field sensitivity of the strain at low magnetic fields was observed for the X = Mn and Ga samples. When the magnetization direction changed from parallel to perpendicular (or vice versa) to the measurement direction, the X = Mn and Ga samples demonstrated a larger strain magnitude at approximately half the magnetic field of CoFe2O4. Therefore, the partial substitution of trivalent ions, particularly Mn3+ and Ga3+ ions for Fe3+ ions, provides an effective strategy to develop superior magnetostrictive materials.