Geometric effects in cylindrical core/shell hard-soft exchange-coupled magnetic nanostructures

We explore the optimal condition for cylindrical core/shell hard-soft exchange-coupled magnetic nanostructures by obtaining full hysteresis loops for various geometries by obtaining full hysteresis loops for various geometrical variables, including the dimensional scale and soft/hard-magnetic phase volume ratio through micromagnetic simulations. For achieving maximum energy product (BH), it is essential to increase the demagnetizing field by increasing the volume fraction of the soft magnet while maintaining a positive nucleation field and, which can be possible by the scaling-down. To scale up the nanostructure to a bulk magnet having high BH can be achieved by forming an array of needle-shaped exchange-coupled cylinders. These findings could lead to the flexible design and scalable fabrication of exchange-coupled permanent magnets.

Automated summary

The optimal condition for cylindrical core/shell hard-soft exchange-coupled magnetic nanostructures was explored through micromagnetic simulations, which showed that increasing the volume fraction of the soft magnet can enhance the demagnetizing field for achieving maximum energy product. Scaling up the nanostructure to bulk magnets with high BH can be achieved by forming an array of needle-shaped exchange-coupled cylinders. These findings have the potential to enable flexible design and scalable fabrication of exchange-coupled permanent magnets.