Magnetic Phase Transitions Through Temperature Change
In the latest issue of Nature Physics, the Planetary Science Institute (PSI) says they’ve observed “how tiny magnets in a special layout align themselves solely as a result of temperature changes.” It was something that had been theoretically predicted but never seen. The process itself occurs in “artificial spin ice,” which could ultimately have implications for better-performing computers.
First some background: when water freezes or goes through a phase transition, the hydrogen and oxygen atoms form a specific, complex structure. In this laboratory setting, however, researchers were able to produce crystals that formed something close to ice (artificial “spin ice”) through magnetic spinning movement. This spin ice is made up of nanomagnets, and their orientation is manipulated through temperature only.
Similar to the atoms in water, the nanomagnets in the spin ice are arranged in a specific, hexagonal structure. People have compared the pattern to a form of Japanese basket weaving called “Kagome.”
Detection and observation are all thanks to “tiny magnetic bridges” or nanobridges, a kind of lithography or printing process and a special microscopy method called photoemission electron microscopy. The scientists were also able to record video footage of the interaction between nanomagnets as the temperature shifts.
The ability to control or manipulate different magnetic phases could lead to improved computer data processing with lower power consumption. One person actually says that this process is based on information processing in the brain!