Recently, the magnetoelectric (ME) effectdielectric polarization of a material under magnetic field, or induced magnetization under an electric field-has become the focus of significant research interests. The primary requirement for the observance of said effect is the coexistence of magnetic and electric dipoles. Most of the known single phase materials suffer from the drawback that the ME effect is quite small, even at low temperatures limiting their applicability in practical devices. Better alternatives are ME composites, which have large magnitudes of the ME voltage coefficient. Composites exploit the product property of materials; where the ME effect is realized by combining magnetostrictive and piezoelectric phases that independently are not ME, but acting together (i.e., their product) result in a ME effect. In this review article, we survey recently reported results concerning ME composites, focusing on ME particulate (synthesized via a controlled precipitation technique) and laminated composites. The article also provides a survey of the compositions and magnitudes of the ME coefficients reported in the literature; a brief description of the analytical models developed to explain and predict the behavior of composites; and discuss several applications that are made possible by enhanced ME effects.

This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr0.52Ti0.48)O3]1−x[(Zn1∕3Nb2∕3)O3]x+yMnCO3, where x=0.1 and y varies from 0.5to0.9wt%. A piezoelectric material with high energy density is characterized by a high product of piezoelectric voltage constant (g) and piezoelectric strain constant (d). The condition for obtaining large magnitude of g constant was derived to be as ∣d∣=εn, where ε is the permittivity of the material and n is constant having lower bound of 0.5. It was found that for all practical polycrystalline piezoelectric ceramic materials the magnitude of n lies in the range of 1.1–1.30 and as the magnitude of n decreases towards unity a giant enhancement in the magnitude of g was obtained. A two step sintering process was developed to optimize a polycrystalline ceramic composition with low magnitude of n. For the optimized composition the value of g33 and d33 was found to be 55.56×10−3m2∕C and 291×10−12C∕N, respectively, yielding the magnitude product d33∙g33 as ∼16168×10−15m2∕N which is significantly higher than the reported values in literature. The magnitude of n for this composition was calculated to be 1.151. This material is extremely promising for immediate applications in the sensing and energy harvesting.

Trilayer composites consisting of 0.9Pb(Zr0.52Ti0.48)O3–0.1Pb(Zn1/3Nb2/3)O3 (0.9 PZT-0.1 PZN) and Ni0.6Cu0.2Zn0.2Fe2O4 (NCZF) in the configuration NCZF-(0.9 PZT-0.1 PZN)-NCZF were synthesized using pressure assisted sintering. Composites with optimized magnetostrictive to piezoelectric thickness ratio showed a high magnetoelectric (ME) coefficient of 525 mV/cm Oe. Further enhancement in the magnitude of ME coefficient was obtained (595 mV/cm Oe) when the angle of applied dc magnetic field was changed to 45°. Changing the intermediate piezoelectric layer from single to trilayer stack geometry configuration leads to the realization of giant ME response of 782 mV/cm Oe in sintered composites.

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