Microscale magnetic compasses

Author(s)
Hidetsugu Shiozawa, Desai Zhang, Michael Eisterer, Paola Ayala, Thomas Pichler, Martha R. McCartney, David J. Smith
Abstract

Microscale magnetic compasses have been synthesized with high yield. These ferromagnetic iron carbide nano-particles, which are encapsulated in a pair of parallel carbon needles, change their orientation in response to an external magnetic field. Electron holography reveals magnetic fields confined to the vicinity of the bicone-shaped particles, which are composed of only a few ferromagnetic domains. Aligned magnetically and encapsulated in an acrylate polymer matrix, these micro-compasses exhibit anisotropic bulk magnetic permeability with an easy axis normal to the needle direction that can be understood as a result of the anisotropic demagnetizing field of a non-spherical single-domain particle. This novel type of material with orthogonal magnetic and structural axes could be highly useful as magnetic components in electromagnetic wave absorbent materials and magnetorheological fluids.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Arizona State University, Technische Universität Wien, Czech Academy of Sciences
Journal
Journal of Applied Physics
Volume
122
No. of pages
6
ISSN
0021-8979
DOI
https://doi.org/10.1063/1.4985838
Publication date
09-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103009 Solid state physics, 103020 Surface physics
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/microscale-magnetic-compasses(4f755d18-da02-411d-81d5-918c8b12ce9c).html