Pairing ferroelectric and ferrimagnetic materials so that their alignment can be controlled with a small electric field at near room temperatures has long been challenging. In the latest issue of Nature, a group of researchers from Lawrence Berkley National Lab and Cornell University reports progress that could lead to ultra low-power microprocessors, storage devices and next-generation electronics.
As the authors note in their paper – Atomically engineered ferric electric layers yield a room-temperature magnetoelectric multiferroic – “Materials that exhibit simultaneous order in their electric and magnetic ground states hold promise for use in next-generation memory devices in which electric fields control magnetism. Such materials are exceedingly…”
Using advanced thin-film deposition, researchers engineered thin, atomically precise films of hexagonal lutetium iron oxide (LuFeO3), a material known to be a robust ferroelectric, but not strongly magnetic. Lutetium iron oxide consists of alternating single monolayers of lutetium oxide and single monolayers of iron oxide, and differs from a strong ferrimagnetic oxide that consists of alternating monolayers of lutetium oxide with double monolayers of iron oxide (LuFe2O4).
“The researchers found that by carefully adding one extra monolayer of iron oxide to every 10 atomic repeats of the single-single monolayer pattern, they could dramatically change the material’s properties and produce a strongly ferrimagnetic layer near room temperature. They then tested the new material to show that the ferrimagnetic atoms followed the alignment of their ferroelectric neighbors when switched by an electric field,” reports an account of the work posted LBNL.
What’s more they achieved this, “at temperatures ranging from 200-300 kelvins (minus 100 to 80 degrees Fahrenheit), relatively balmy compared with other such multiferroics that typically work at much lower temperatures. “Developing materials that can work at room temperature makes them viable candidates for today’s electronics,” said study co-lead author Julia Mundy, a University of California Presidential Postdoctoral Fellow and an affiliate at Berkeley Lab. “The multiferroic we created takes us a major step toward that goal.”
Link to Nature paper: http://www.nature.com/nature/journal/v537/n7621/full/nature19343.html#access
Link to LBNL article: http://newscenter.lbl.gov/2016/09/21/coupling-magnetic-electric-materials/