Temperature Dependence of Magnetostrctive Properties of Cu_0.6Co_0.4Fe₂O₄ and CoFe₂O₄ below Room Temperature

抄録

The temperature dependence of the magnetostrictive properties of Cu_0.6Co_0.4Fe₂O₄ and CoFe₂O₄ samples was investigated. At 300 K, the strain magnitude of the Cu_0.6Co_0.4Fe₂O₄ sample increased with increasing magnetic fields and reached a maximum value at approximately 0.8 T. Upon further increasing the magnetic fields, the strain magnitude gradually decreased and almost saturated at 7 T. Compared to the CoFe₂O₄ sample, the Cu_0.6Co_0.4Fe₂O₄ sample exhibited a more pronounced increase in the strain magnitude as the temperature decreased. In addition, the strain magnitude at 7 T of the Cu_0.6Co_0.4Fe₂O₄ sample exhibited a clear maximum at 100 K, unlike that obtained of the CoFe₂O₄ sample. The Cu_0.6Co_0.4Fe₂O₄ sample showed a strain of approximately 911 ppm at 100 K by changing the direction of 7 T magnetic field, which is significantly larger than that of the CoFe₂O₄ sample. Thus, the Cu_0.6Co_0.4Fe₂O₄ sample showed a larger strain magnitude than the CoFe₂O₄ sample in the temperature range of 10–300 K. Therefore, the partial substitution of Cu for Co is very effective in enhancing the magnetostrictive properties of CoFe₂O₄ across a wide temperature range, including room temperature.