Fabrication and Characterization of Polymer-Bonded Flexible Anisotropic Micro-Magnet Arrays

Erika Fontana (1) , Lucie Motyckova (1) , Caterina Tomba (2) , Frederico Orlandini Keller (1) , Georgiana Groza (1) , Marlio Bonfim (3) , Laurent Ranno (1) , Thibaut Devillers (1) , Nora Dempsey (1)

1 NEEL - MNM - Micro et NanoMagnétisme
2 INL - Institut des Nanotechnologies de Lyon
3 UFPR - Universidade Federal do Parana [Curitiba]

Here we present a process for the fabrication of arrays of anisotropic flexible bonded micro-magnets attached to a transparent base. The micro-magnets are based on hard magnetic SmFeN or Sr-ferrite powders mixed with polydimethylsiloxane (PDMS). The size, shape and distribution of the micro-magnets are defined using a Si-mould fabricated by deep reactive ion etching (DRIE). The volume fraction of the magnetic powder was fixed at 30% while the thickness of the micro-magnets ranged from 50-300 μm and their in-plane dimensions from 20-400 µm. Powder alignment was achieved using a bulk NdFeB magnet. Arrays of micro-pillars of height 300 µm and width tapering from 300 µm at their base to 200 µm at their top were characterized using vibrating sample magnetometry (VSM) and Scanning Hall Probe Microscopy (SHPM) and the results of the latter were compared with analytical simulations. The homogeneous magnetic field produced by a 3-axis electromagnet was used to move the micro-pillars in a controlled fashion. The field induced in-plane displacement of the SmFeN-based pillars was more than three times greater than that of the Sr-ferrite-based ones, reaching 13 µm at the maximum applied field value of 100 mT.

Mots clés: anisotropic bonded magnet; flexible polymer-bonded magnet; hard magnetic material; SmFeN

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Electromagnétisme

Erika Fontana, Lucie Motyckova, Caterina Tomba, Frederico Orlandini Keller, Georgiana Groza, et al.. Fabrication and Characterization of Polymer-Bonded Flexible Anisotropic Micro-Magnet Arrays. IEEE Transactions on Magnetics, 2021, 58 (2), pp.1-5. ⟨10.1109/TMAG.2021.3088048⟩. ⟨hal-03598515⟩