Particles that respond to a field

01 / WHAT CHANGES

The mechanism

Some magnetite nanoparticles (Fe₃O₄), when sufficiently small and under suitable conditions, can exhibit superparamagnetism: they respond to a field, but their average magnetisation may disappear when it is removed. Composition, size, temperature and interactions are crucial. Not all iron oxides behave in the same way.

02 / WHERE IT LEADS

An application, in context

Magnetic separation makes it possible to investigate particle recovery from a dispersion. Efficiency depends on the field and its gradient, particle size and aggregation state.