Interacting magnetic nanoparticles as building blocks for miniaturized magnetic tags in anticounterfeiting strategies

Miniaturized, unique, stable, and information-rich tags are crucial for anticounterfeiting efforts in the handling and distribution of consumable goods. Despite ongoing research into various tag technologies, a systematic approach to engineering their physical properties for optimal security is often missing. Through a numerical approach focused on in-depth modeling of the interacting magnetic nanoparticle properties, we demonstrate how their collective magnetic behavior, after suitable field conditioning, boosts the security of magnetic tags. Our miniaturized tag leverages the nonlinear response of assemblies of interacting <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mi>Fe</a:mi> <a:mn>3</a:mn> </a:msub> <a:msub> <a:mi mathvariant="normal">O</a:mi> <a:mn>4</a:mn> </a:msub> </a:math> nanoparticles to store custom information into binary keys. The magnetic properties of the nanoparticles and their spatial correlations result to be crucial to effectively decorrelate all keys from a large batch of tags produced under identical conditions. This ensures each tag encodes unique, virtually unclonable information, guaranteeing secure product identification, traceability, and quality control, enhancing consumer safety and fighting counterfeiting. The tag stability against transient disturbances of thermal and magnetic nature has been assessed. Our numerical analysis establishes magnetic nanoparticle tags as highly promising primitives characterized by high entropic information and security resilience to cloning, paving the way to better-engineered devices that harness the collective magnetic properties of nanoparticles.