Postprint version. Published in Magnetic Properties of Fine Particles: Proceedings of the International Workshop on Studies of Magnetic Properties of Fine Particles and Their Relevance to Materials Science, January 1, 1991, pages 393-402. Copyright © 1992 Elsevier. The definitive version is available at http://www.elsevier.com.
Two examples of biological magnetic fine particles are considered: iron-storage proteins and magnetotactic bacteria. These cover many aspects of this field, including the use of well-defined biological systems for testing theoretical models, using magnetic properties to distinguish between different biological materials, producing magnetic materials by biological processes, and using optimised biological magnetic systems as a guide to the production of synthetic magnetic materials.