Controlling cooperative phenomena in nanomagnetic systems - New physics and its application

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This research program will make possible the next generation of devices and applications based on controlled magnetism at the nanoscale by following three complementary themes. Firstly, my group will continue to pioneer discoveries into the physics of cooperative phenomena driving magnetism in macro-sized crystals made of nanoparticles. By using nature's inherent mechanisms to drive three-dimensional self-assembly of nanoparticles, the well known atom's magnetism is enhanced by ten-thousand-fold in nanoparticles. Our work investigates the unique properties of magnetic nanoparticles forming different crystal structure environments. Magnetic ordering from interactions between atoms in a crystal is a well understood phenomenon. By contrast, amongst nanoparticles in a structurally ordered configuration, the magnetism is largely unexplored. Secondly, my group will research how to recapture the magnetism lost due to finite size and surface effects - especially prevalent amongst iron-oxide and ferrite-based nanoparticles that are the basis of a large amount of applied physics. Surface magnetism is disordered and this frustrates a nanoparticle from achieving its maximal magnetization. We are discovering ways of control via tuning quantum confinement effects and identifying the physics of the cooperative phenomena that surface and core atomic moments undergo. Short term benefits include using nanoparticles as vehicles optimized for drug delivery, MRI magnetic contrast agents and improved magnetic hyperthermia. Thirdly, my group is investigating ferromagnetism and antiferromagnetism (the two fundamental forms of cooperative phenomena at the atomic-scale) and how they interact at the limit of today's technology and beyond. Proximity effects and parts with compositional and structural constrictions dominate the physics of the magnetism at the nanoscale. By considering ways to control magnetic properties like anisotropy and domain configuration, we will acquire a better understanding of relevant devices such as hard-drive read/write heads and spin-valves used in 'spintronic'-based devices.