Composite Magnetoelectrics

3

Layered multiferroic composites

G. Srinivasan     Oakland University, Rochester, MI, USA

Abstract

In a composite consisting of magnetostrictive and piezoelectric phases, the magnetoelectric (ME) effect is the result of a “product-property,” that is the mechanical deformation due to magnetostriction results in a dielectric polarization due to the piezoelectric effect. The early works on ME composites dealt with CoFe₂O₄ and BaTiO₃ and were prepared by two methods: sintering and unidirectional solidification of eutectic melts. Both types of composites developed microcracks due to thermal expansion mismatch and yielded ME coefficients that were a factor 40–60 smaller than calculated values. Possible causes include (1) microcracks, defects, and impurities ...