A four-state magnetoelectric coupling for embedded piezoelectric/magnetic composites.

Magnetoelectric (ME) behavior for PZT/Ni composites with PZT embedded in Ni is investigated. The embedded composites show a four-state phenomenon of ME coupling. Upon applied magnetic fields, polarization reversal occurs when the applied static magnetic field exceeds a certain value. Based on the experimental data, a geometric factor k is proposed which captures the size effect on the ME behavior. To quantify the ME behavior of the embedded composites, finite element analysis is performed, which fits well with the experimental data. The calculation enables us to deduce that the four-state ME coupling is related to the change of the compressive force on the contact surfaces between PZT and Ni upon the applied magnetic field. The results are of importance for both the basic understanding of the ME coupling in the embedded PZT/Ni composites and the potential device applications, such as four-state memory devices, magnetic field switches, etc. [ABSTRACT FROM AUTHOR]