A composite element (CE) bit design for magnetically encoded microcarriers provides an increased coercivity range for longer bit codes as well as significant improvements to encoding density, reliability and read-out.The authors gratefully acknowledge the EPSRC for financial
support and thank Dr Andrew Thompson for valuable discussions.
DL, TM and CHWB acknowledge the Cambridge Philosophical
Society, the Lundgren Research Award, the
Development of Prototype Grant (Innovate UK), the Brian
Mercer Feasibility Award (Royal Society) and Cambridge Bio-
Magnetics Ltd. AFP acknowledges the Winton Programme for
the Physics of Sustainability.This is the final published version. It first appeared at http://pubs.rsc.org/en/Content/ArticleLanding/RA/2015/C4RA16991C#!divAbstract