We present fabrication of a novel (Nd_0.7Ce_0.3)_10.5Fe_83.9B_5.6 magnetic powder and polydimethysiloxane bonded material that can be micropatterned into micromagnets. The magnetic powder, with an average particle size of 5μm-6μm, has been prepared from an alloy ingot of raw materials which are put in a vacuum induction furnace and melt spun to obtain ribbons with nanocrystalline microstructure. The ribbons are crushed using vibrating ball milling under inert atmosphere to obtain coarse powder (average particle size of 200μm). In order to obtain 5μm fine powder the course powder is jet milled at 6000rpm under inert atmosphere. The fine magnetic powder (referred to as MQFP-15) is ultrasonically uniformly dispersed in a polydimethylsiloxane matrix (PDMS) using a horn tip probe operating at a frequency of 42 kHz. Micromagnets (diameter of 50μm, height 30μm) are fabricated from the prepared composite via soft lithography and are tested using a SQUID magnetometer, showing a remanent magnetization (M_r) of 60.10 emu/g and coercivity (H_c) of 5260 G at 75 weight percentage of magnetic powder in the PDMS matrix.

Date Published: 17 February 2010
PDF: 8 pages
Proc. SPIE 7593, Microfluidics, BioMEMS, and Medical Microsystems VIII, 759316 (17 February 2010);

Published in SPIE Proceedings Vol. 7593:
Microfluidics, BioMEMS, and Medical Microsystems VIII
Holger Becker; Wanjun Wang, Editor(s)