Shell Nano Magnets

About

Description High performance magnets are critical components in energy technologies. Growing awareness of economic limitations associated with rare-earth containing materials has stimulated innovative research efforts to replace rare earth containing magnets. With this in mind and the need to outperform current technologies by developing larger energy products, nanostructured magnets consisting of hard-soft single domain cores using transition metals is a viable solution. It has been postulated that patterned nanocomposites consisting of hard and soft magnetic domains can achieve a 6-fold improvement in energy product over simple hard magnets due to magnetic exchange behavior at the nanoscale. We have developed synthetic protocols that allow the isolation of soluble, mesoscale assembled hard-soft core shell exchange spring magnets. The materials are produced in a unique way allowing for control of the shell thickness which increases both magnetic remnance and coercivity providing a dramatic increase in the energy product value.  FePt/Co is one such example. A 5nm hard magnetic FePt core and a soft magnetic 0.6-2.3 nm thick Co shell were chemically prepared. The variation in shell thickness allows the achievement of double the coercivity which generates approximately a 3.5-fold increase in the energy product for FePt/Co relative to FePt.