Enhanced magnetoelectric coupling performance in CoFe2O4 @BaTiO3 multiferroic liquid by tuning the CoFe2O4 morphology

Multiferroic materials are identified as a newly emerging area of research because of their obvious magnetoelectric effects between ferroelectric and ferromagnetic orders. This paper uses the ball milling method to prepare CoFe2O4 @BaTiO3 (CFO@BTO) multiferroic liquids with different CoFe2O4 (CFO) particle morphologies. The settling stability and magnetoelectric properties of the CFO@BTO multiferroic liquids with different CFO particle morphologies have been systematically studied. XRD analysis confirmed that the crystal structure of the powders was consistent with that of standard cards, and the CFO powders exhibited irregular spherical shapes, well-dispersed rectangular shapes, and uniform nanowires. TEM images revealed a core-shell structure of the formed particles. The study found that as the CFO particle morphology changed from spherical to rectangular and then to nanowire, both the residual magnetization intensity (Mr) and saturation magnetization intensity (Ms) of both CFO powder and CFO@BTO composite powder increased gradually. The settling rate of the multiferroic liquids with spherical CFO morphology was observed to be 4.6% with good settling stability after resting for 48 h. The dielectric constant and dielectric loss showed similar trends in the presence and absence of magnetic fields. With the change in CFO particle morphology, the maximum polarization strength (Pmax), residual polarization strength (Pr), and coercivity field strength (Ec) of the multiferroic liquids gradually increased. The magnetoelectric coupling coefficient of the multiferroic liquids was found to be the largest when the CFO morphology was rectangular, measuring 23.93 V/(cm·Oe). The study provides insights into improving the magnetoelectric coupling effect of multiferroic materials and opens up new possibilities for further research in this area.