Multiferroic materials possess two or more ferroic orders such as ferroelectric, ferromagnetic, or ferroelastic. Multiferroic magnetoelectric (ME) materials exhibit direct coupling between the ferroelectric and ferromagnetic order parameters. In composites, ME effect is a combination of two types of material property such as magnetostriction and piezoelectricity. On application of magnetic field, magnetostrictive phase produces strain which is transferred on to the piezoelectric phase that converts strain into electric charge. This conversion of applied magnetic field into electric field is termed as direct ME effect. On the other hand, under applied electric field piezoelectric phase produces strain which is transferred on to the magnetostrictive phase that converts it into magnetic field, termed as converse ME effect [1]. Figure 16.1 shows that ME materials exhibit cross-coupling between the applied magnetic field and electric polarization or vice versa.In general, ME materials are categorized into four groups (i) single-phase materials, (ii) 3-0 type particulate composites, (iii) 2-2 type laminate composites, and (iv) 1-3 type cylinder-matrix composites. Single-phase materials exhibiting ME effects should show two coupled-transitions: one from ferroelectric to paraelectric state, and another from ferro/ferri/antiferro-magnetic to paramagnetic state: the ME effect then arises due to coupling between the magnetic and polar sublattices. Recent investigations of single-phase multiferroics have revealed that the origin of ME effect is often associated with a particular exchange mechanism for various families of compounds such as: orbital ordering, Jahn-Teller distortion, super/ double exchange, and/or geometric magnetic frustration. Unfortunately, singlephase materials suffer from the drawback that the ME effect is extremely small at room temperature. For example, the highest ME coefficient has been reported for