The presence of coupling between electric and magnetic fields attracts various applications for magnetoelectric (ME) materials such as magnetic field sensors, energy harvesting devices, multiferroic motors, etc. ME effects are produced due to transfer of strain through bonding of ferroelectric and ferromagnetic constituent phases. ME effects are significantly affected by various parameters such as the constituent phases, geometry, connectivity schemes, etc. In the present work, a trilayered ME composite is made by sandwiching a ferroelectric material between two ferromagnetic materials at the top and the bottom. ME composites were made by varying the volume fractions of the ferromagnetic material. This work primarily focuses on understanding the temperature dependence of sensing characteristics and coupling factor of ME composites. With this in mind, initially the temperature dependent behavior of individual constituent phases are experimentally investigated. Experimental investigation reveals that the sensing characteristics and coupling factor of ME composites are significantly affected by the operating temperature and the volume fraction of the constituent phases. © 2018 IOP Publishing Ltd.

Arunachalakasi Arockiarajan

Department of Applied Mechanics

Sk M. Subhani

Couplings

Energy harvesting

Ferroelectricity

Ferromagnetic materials

Ferromagnetism

Magnetic field effects

Temperature distribution

Volume fraction

CHARGE COEFFICIENTS

Electric and magnetic fields

Energy harvesting device

Experimental investigations

MAGNETOELECTRIC COMPOSITES

ME VOLTAGE COEFFICIENTS

SENSING CHARACTERISTICS

Temperature dependent behavior

Ferroelectric materials

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Physics D: Applied Physics

An experimental investigation has been carried out to capture the magneto-mechanical behavior and material parameters of magnetostrictive material. Further, the experimental study is extended to capture the magnetoelectric (ME) coupling response of trilayered composites by applying both alternating and static magnetic fields. From the experiments, it is observed that the magnetostrictive material has a nonlinear hysteretic behavior. Hence, a three dimensional (3-D) nonlinear constitutive model has been proposed based on a thermodynamic framework and multisurface plasticity. In ME composites, it is also observed that a large ME coupling response can be obtained while operating near resonance frequencies. To capture the resonant ME effects, a theoretical formulation has been proposed based on axial vibrations theory and the proposed constitutive model has been incorporated in the formulation. The simulated resonant ME coupling response based on the proposed formulation is compared with the experimental data and found to be in agreement with each other. Further, a parametric study has been performed to address the variation of the resonant ME response as a function of various parameters such as axial compliance ratio, volume fraction of constituents, temperature, direction of magnetic loading and aspect ratio. This study reveals that the coupling response can be optimized by choosing the suitable parameters based on design requirement. © 2019 Elsevier Masson SAS

European Journal of Mechanics, A/Solids

Study on axial resonance magneto-electric (ME) effects of layered magneto-electric composites

Magnetoelectric core-shell nanocomposites have tremendous applications in biomedical sectors such as targeted and controlled drug delivery for cancer treatment and non-invasive brain stimulation for treatment of Parkinson's disease. The neural activity deep in the brain is triggered with the help of these magnetoelectric nanocomposites by externally applied magnetic fields, since these materials exhibit substantial magneto-mechano-electrical coupling. Also, they posses better connectivity between the ferroelectric and ferromagnetic phases without interface effects. BaTiO 3 (BTO) and CoFe 2 O 4 (CFO) exhibits significant ferroelectric and ferromagnetic properties which are able to induce effective multiferroic properties. Core-shell nanocomposites of CoFe 2 O 4 as core and BaTiO 3 as shell, were synthesized by co-precipitation and sol-gel techniques, respectively. The optimum calcination temperature required to get pure BaTiO 3 phase was observed to be 900 ∘ C. The tetragonal phase of pure BaTiO 3 and the spinal perovskite structure of pure CoFe 2 O 4 was in accordance with the X-ray diffraction patterns. The core-shell type morphology of the synthesized nanocomposites were corroborated using Transmission Electron Microscopic images. The piezoelectric and magnetization response of these magnetoelectric nanocomposites were captured as functions of temperature and volume fractions of individual phases. © 2019 Elsevier Ltd and Techna Group S.r.l.

Ceramics International

Influence of individual phases and temperature on properties of CoFe 2 O 4 -BaTiO 3 magnetoelectric core-shell nanocomposites

In this work, experiments have been performed to study the magneto-mechanical behaviour of (Tb0.3Dy0.7Fe2) under various operating temperatures. Based on the experimental results, a three dimensional nonlinear constitutive model under thermodynamic framework have been developed to capture the thermo-magneto-mechanically coupled behaviour. Then, the model parameters have been identified using least square approximation. Later, using the developed model, a homogenisation procedure has been introduced to simulate magnetoelectric (ME) coupling behaviour for various temperature and volume ratio of composition for different configurations (T-T, L-T, T-L, L-L) in layered ME composites. In a particular configuration (say L-T) is represented by referring first letter (L) as the direction of external magnetic field and the second letter (T) as the direction of polling in the piezoelectric material. Consequently, an experimental setup has been established to capture the ME voltage coefficient at L-T mode under different operating temperatures. Comparison between the experimental data and the simulation results shows good agreement with each other. Comparing the ME coupling behaviour for various configurations, L-L and L-T configurations are observed to have higher coupling factor. © 2018 Elsevier Ltd

Mechanics of Materials

Theoretical and experimental analysis of temperature dependent nonlinear behaviour of tri-layered magnetoelectric composites

Materials

Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures

Applied Physics Letters

Thermal stability of magnetoelectric sensors

Journal of Materials Science

Low-frequency magnetoelectric interactions in single crystal and polycrystalline bilayers of lanthanum strontium manganite and lead zirconate titanate

Physics Letters A

Dielectric behaviour in magnetoelectric composites

Experimental investigation of performance of tri-layered magnetoelectric composites under thermal environment

Journal	Journal of Physics D: Applied Physics
Publisher	Institute of Physics Publishing
ISSN	00223727
Open Access	No