Multiferroic magnetoelectric materials, which simultaneously exhibit ferroelectricity and ferromagnetism, have recently stimulated a sharply increasing number of research activities for their scientific interest and significant technological promise in the novel multifunctional devices. Natural multiferroic single-phase compounds are rare, and their magnetoelectric responses are either relatively weak or occurs at temperatures too low for practical applications. In contrast, multiferroic composites, which incorporate both ferroelectric and ferri-/ferromagnetic phases, typically yield giant magnetoelectric coupling response above room temperature, which makes them ready for technological applications. This review of mostly recent activities begins with a brief summary of the historical perspective of the multiferroic magnetoelectric composites since its appearance in 1972. In such composites the magnetoelectric effect is generated as a product property of a magnetostrictive and a piezoelectric substance. A...

Multiferroic magnetoelectric composites: Historical perspective, status, and future directions

Analytical and experimental determination of the material intrinsic length scale of strain gradient plasticity theory from micro- and nano-indentation experiments

Size dependent strengthening in particle reinforced aluminium

Computational microstructure characterization and reconstruction: Review of the state-of-the-art techniques

Mechanical properties of Al-based metal matrix composites reinforced with Zr-based glassy particles produced by powder metallurgy

The influence of particle size and particle fracture on the elastic/plastic deformation of metal matrix composites

A recently developed multiple-scattering approach for calculating the coupled electrical–mechanical response of composites is generalized to treat more-complicated coupling between the constituent phases. This provides a unified theoretical framework for determining the effective properties of ferroelectric and/or ferromagnetic composites with any multifield coupled interaction between electrical, magnetic, mechanical, and thermal effects. Among the advantages of the theory is its simplicity of formulation, which is suited to computation. The common non-self-consistent approximation (NSCA) and self-consistent effective medium approximation (SCEMA) of the theory are discussed through application to a number of piezoelectric, pyroelectricpyromagnetic, and magnetoelectric composites.

Effective properties of ferroelectric and/or ferromagnetic composites : A unified approach and its application

Throughout the microstructure at every varistor, there exist variations of the grain size and the electrical properties of the individual grain boundaries. To calculate the effect of such microstructural variations on the overall electrical transport properties, we describe a multibond percolation approach utilizing effective medium theory. The model presented takes into account these variations as well as the electrical conductivity of the ZnO grains themselves. To illustrate the predictions of the model, both the effect of continuous distributions in the grain boundary potential and the grain size are considered, as well as a bi-lognormal distribution in grain size to represent the effect of a population of anomalously large grains in a smaller grain size varistor.

Effect of variations in grain size and grain boundary barrier heights on the current-voltage characteristics of ZnO varistors

The effective piezoelectric moduli of polycrystalline piezoelectric ceramics are calculated using a straightforward averaging method (a Voigt average) and a more rigorous effective-medium theory recently developed for piezocomposites The effects of polarization orientation within each crystallographic domain and the shape of the domain on the effective piezoelectric moduli are presented The effective-medium theory, which includes full coupling of the elastic and dielectric interactions, gives results in reasonable agreement with experimental ones

Ce-Wen Nan

Papers

The influence of particle size and particle fracture on the elastic/plastic deformation of metal matrix composites

Effective properties of ferroelectric and/or ferromagnetic composites : A unified approach and its application

Effect of variations in grain size and grain boundary barrier heights on the current-voltage characteristics of ZnO varistors

Piezoelectric Moduli of Piezoelectric Ceramics