Creation of a Macroscopic Ground State Magnet or "Macromagnetic Atom"

This document presents the theoretical and experimental design of a new type of macroscopic permanent magnet, inspired by the magnetosome chains that occur naturally in magnetotactic bacteria. It proposes the construction of a “macromagnetic atom”: a hierarchical structure formed by perfectly aligned magnetite (Fe3O4) nanoparticles, encapsulated in a PEEK (Poly-Ether-Ether-Ketone) matrix, which act as a single coherent and stable magnetic dipole at the macro scale. The fabrication process is described in detail: from the purification and alignment of magnetosomes under a magnetic field, their self-assembly into one-dimensional chains, structural encapsulation in a resistant polymer, and their subsequent modular organization to scale the structure to the centimeter level. The result is a macroscopic single-domain magnet with permanent remanence, high structural coercivity, and great thermal and mechanical stability. Additionally, a quantitative comparison is made between the achievable magnetic properties of these magnetosome-based magnets (remanence, coercivity, (BH)max, Curie temperature, density) versus conventional NdFeB magnets. The redefinition of coercivity as an emergent structural property, beyond the base material, is highlighted. The document demonstrates the feasibility of manufacturing a high-performance magnet without rare earths, with a strong ecological and strategic focus. The document concludes with an exploration of potential applications in energy, sensors, magnetoelectronic devices, quantum systems, soft robotics, and sustainable technologies. It positions the “macromagnetic atom” as a bio-inspired and highly promising alternative for the new generation of advanced magnetic materials.