Dr. Roland Winkler from the Physics Department at Northern Illinois University delivered a presentation at Northern Exposure, which takes place at the 71 North Partnership Studio on Fridays from 1:00-2:00 p.m. in Founders Library at NIU.
Dr. Winkler spoke about the history of magnetism and a significant scientific breakthrough in the field. For many years, physicists recognized only two types of permanently magnetic materials: ferromagnets (FMs) and antiferromagnets (AFMs). In ferromagnetic materials like iron, the unpaired electrons on atoms spin in the same direction, creating parallel alignment of the tiny atomic magnets. In antiferromagnetic materials, neighboring electrons spin in opposite directions, creating an antiparallel arrangement where the magnetic effects cancel each other out, resulting in zero net magnetism.
The newly discovered class of magnetic materials, known as altermagnets, represents a groundbreaking development. These materials were previously misclassified as antiferromagnets but are now recognized as having unique properties that bridge the gap between ferromagnets and conventional antiferromagnets.
Magnetic materials have important practical applications, particularly in devices like hard disk drives where they enable non-volatile data storage. One of their key advantages is the ability to maintain their magnetic state without requiring a continuous power supply. However, ferromagnetic materials have the drawback of being susceptible to manipulation and interference from external magnetic fields.
A major goal driving current research in magnetic materials is the pursuit of technology that would allow computers to be completely switched off when not in use, rather than continuously draining battery power in standby mode. While antiferromagnets offer greater robustness compared to ferromagnets, they present significant challenges in practical applications. Altermagnets, with their intermediate properties, may provide promising new opportunities for advancing this research and developing more energy-efficient computing technologies.