Strong optical Tellegen effect using cobalt–silicon nanocone metasurface spontaneously magnetizes without external magnetic field

https://www.eurekalert.org/news-releases/1118417

"overcomes extreme weakness of this effect in non-engineered materials... 100X stronger response combining magnetic/ dielectric components at nanoscale... allows electric fields to directly drive magnetic responses in nonreciprocal way... nonreciprocal optical devices (like isolators with light travel in 1 direction) not needing bulky external magnets. compatible with large-area nanofabrication, making scalable for next-generation photonic chips and advanced optical communication systems"