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Domain Walls in Multiferroic Materials and Their Functional Properties
Published in Tamalika Banerjee, Oxide Spintronics, 2019
In recent years, the so-called multiferroic materials, those which display ferroelectricity and magnetism in the same phase, have obtained a lot of attention because of their potential to present large magnetoelectric effect. This is of fundamental interest, but also of technological importance because it would allow to control the magnetization (polarization) of devices with an electric (magnetic) field. According to symmetry arguments and using a Landau approach, the magnetoelectric terms in the Gibbs free energy would be Φ=Φ0−αikEiHk−1/2βijkEiHk−1/2γijkHiEjEk
Layered Two-Phase Magnetoelectric Materials
Published in Sam Zhang, Dongliang Zhao, Advances in Magnetic Materials, 2017
Zhaofu Du, Sam Zhang, Dongliang Zhao, Tat Joo Teo, Rajdeep Singh Rawat
Magnetoelectricity is the most important effect of multiferroic materials that exhibits the change of electric polarity under an external magnetic field. The change of magnetization polarity in an external electric field is referred to as converse magnetoelectric effect (CME). Magnetoelectric (ME) effect and CME coefficients are defined as follows [2]: () αME=δEδHorαME=dpdH () αCME=δBδEorαCME=μ0dmdH
Electrical characterization of electro-Ceramics
Published in Amit Sachdeva, Pramod Kumar Singh, Hee Woo Rhee, Composite Materials, 2021
Multiferroic ceramics are a probable explanation for the magnetoelectric effect. The magnetoelectric effect is analogous to the manifestation of dielectric polarization in the presence of a strong magnetic field. This can also be termed a straight magnetoelectric effect and is considered to be a magnetoelectric effect (P = αH). The converse magnetoelectric effect can be explained as magnetization upon which an electric field is applied and considered a magnetoelectric effect (M = αE). The above converse and direct magnetoelectric effects show an effectual conversion between energies of electric fields and magnetic fields.
Reflection of plane waves at the stress-free/rigid surface of a micro-mechanically modeled Piezo-electro-magnetic fiber-reinforced half-space
Published in Waves in Random and Complex Media, 2022
Sonam Singh, A. K. Singh, Sayantan Guha
Piezoelectric materials are smart materials that can convert mechanical energy to electrical energy (direct Piezoelectric effect) and electrical energy to mechanical energy (indirect Piezoelectric effect). Piezoelectric materials are used to design many ultrasonic instruments dependent on either surface acoustic waves or bulk acoustic waves for a multitude of applications. Because of their high sensitivity, wide bandwidth, and improved reception characteristics, these devices are commonly modeled with a layered geometry. In the past decades, several noteworthy research works have been conducted on monolithic smart materials such as Piezoelectric materials and magneto-electric (or simply, magnetic) materials, covering the aspects of material characterization as well as modeling of waves propagating through these materials [1–5]. It is witnessed that under mechanical and/or electrical loading, failure of devices generally occurs either due to the brittle nature of these materials or the existence of possible defects of impurities, cavities, and micro-cracks. It is also hard to fully utilize Piezoelectric materials due to some of their disadvantages, such as rigidity and low Piezoelectric constants. Thus, with the growing requirement of high-performance and better-sensing devices in medical, engineering, aerospace, automobile, and geological applications, the field of material characterization and wave propagation aspects in these materials needs to upgrade and move towards more improved materials which possess the required properties to overcome the flaws of these materials. In view of these requirements, the idea of altering or customizing the micro-structure of monolithic materials has emerged. Under this concept, the properties of Piezoelectric materials are tailored by adjoining a second phase depending on the specific scientific/engineering applications. One such material is the composite Piezo-electro-magnetic (PEM) material which has improved properties over the monolithic Piezoelectric and Piezo-magnetic materials due to its magnetoelectric coupling [6]. Like the Piezoelectric effect, the magnetoelectric effect has also gained considerable attention from researchers because of its significant applications in broadband magnetic field probes, which exhibit large magneto-electric effects and exceptionally flat frequency response. The emergence of an electric polarization or magnetization due to an applied electric or magnetic field is the main outcome of coupled magneto-electric field effect. When a magnetic field is applied to a composite of the Piezoelectric perovskite and the spinel structure phases, the ferrite particles change their shapes because of magnetostriction, and the strain is passed along to the Piezoelectric particles, resulting in an electrical polarization. The magneto-electric effect obtained in this way can reach a hundred times larger than that in the single-phase magneto-electric material. Researches concerned with the characterization of PEM materials may be referred through the works of Nan [7], Li and Dunn [8], and Ke et al. [9]. Analysis of wave propagation in this advanced composite PEM material has been done by Singh and Singh [10] and Sharma and Kumar [11].