"Magnetic particles" refer to tiny objects that can be magnetized, meaning they can become attracted to magnets or exhibit magnetic properties. Full definition
The mixture was then dried, leaving behind an elastic polymer thin film embedded with the aligned chains of magnetic particles. (sciencedaily.com)
Alternatively the motors can be lined with magnetic particles, allowing external steering using magnets. (nanotechweb.org)
Scientists haven't spotted any yet, but a new experiment offers an unprecedented glimpse at what these elusive magnetic particles should look like. (sciencenews.org)