|
|
Mellado, P., Concha, A., & Rica, S. (2020). Magnetoelectric Effect in Dipolar Clusters. Phys. Rev. Lett., 125(23), 237602.
Abstract: We combine the anisotropy of magnetic interactions and the point symmetry of finite solids in the study of dipolar clusters as new basic units for multiferroics metamaterials. The Hamiltonian of magnetic dipoles with an easy axis at the vertices of polygons and polyhedra, maps exactly into a Hamiltonian with symmetric and antisymmetric exchange couplings. The last one gives rise to a Dzyaloshinskii-Moriya contribution responsible for the magnetic modes of the systems and their symmetry groups, which coincide with those of a particle in a crystal field with spin-orbit interaction. We find that the clusters carry spin current and that they manifest the magnetoelectric effect. We expect our results to pave the way for the rational design of magnetoelectric devices at room temperature
|
|
|
|
Pabba, D. P., Rao, B. V. B., Thiam, A., Kumar, M. P., Mangalaraja, R. V., Udayabhaskar, R., et al. (2023). Flexible magnetoelectric PVDF-CoFe2O4 fiber films for self-powered energy harvesters. Ceram. Int., 49(19), 31096–31105.
Abstract: Integrating the concept of magnetoelectric in the mechanical energy harvesters through the magneto-mechanoelectrical (MME) nanogenerators has been explored to realize the self-powered devices. The magnetoelectric interaction enabled the output performance of the MME nanogenerator under magnetic stimulus of the active components of the energy harvesters. In this perspective, we fabricated a flexible biomechanical and MME nanogenerator using PVDF/CoFe2O4 fibers composite films. CoFe2O4 fibers were synthesized by the electrospinning technique and the process parameters were optimized to achieve uniform and bead-free fibers. The structural and morphological properties were investigated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The structural and morphology revealed the fibers calcined at 800 degrees C with a heating rate of 2 degrees C/min produced bead-free continuous fibers with a fiber diameter of 210 nm with cubic spinel crystalline structure with a crystallite size of 34 nm. These highly crystalline fibers were used to fabricate PVDF/CoFe2O4 fibers composite films. The magnetoelectric behaviour of the films verified through polarization vs. electric field (P-E) loops under magnetic field. The leakage current density and mechanism of the composite films were investigated, and it was discovered that the mechanism was due to Schottky emission. Further the energy harvesting performance of the composite films were estimated where the nanogenerator achieved an output voltage of 13 V under biomechanical tapping force while the MME nanogenerator produced 3.5 V under a low frequency stray magnetic field of 6 Oe with a power density of 28 & mu;W/m2.
|
|
