Nickel Magnetic Metalattices

Magnetic metalattices are highly structured on a small scale of nanometers with many voids and interconnections. On this very small scale, the lines of magnetization within the ferromagnet are resistant to bending to follow the contours of the convoluted interior surfaces, yet they also prefer not to terminate on the interior surfaces, since that would increase the magnetostatic energy. Faced with these competing requirements, modeling predicts that nature finds interesting compromises. In particular, the magnetization pattern can jump abruptly between various topologically distinct states: spirals, hedgehogs, streams, etc. as a function of the external magnetic field applied. Unlike the transient patterns that appear during a field reversal in a regular bulk magnet, these topologically distinct states are stable and persistent. Using high pressure confined chemical vapor deposition we have infiltrated the voids between nanoscale (14 nm to 100 nm diameter) silica spheres with nickel to form nickel metalattices. The resulting structures are nearly void free and highly interconnected, unlike isolated nickel metal nanoparticles. Whereas nickel nanoparticles behave as independent superparamagnets, nickel metalattices behave magnetically as truly interconnected yet nanoscale systems. Direct exchange between the nickel “meta-atoms” of the metalattices mediated by “meta-bonds” thus seems likely.