Nonlinear multimodal electromagnetic device for vibration energy harvesting K. Aouali, Z. Zergoune, N. Kacem, E. Mrabet, N. Bouhaddi and M. Haddar MATEC Web Conf., 286 (2019) 01003 Published online: 14 August 2019 DOI: 10.1051/matecconf/201928601003