Half Ice , Half Fire : Physicists Discover a New Phase of Matter Hidden in a Magnetic Compound

Physicists at Brookhaven National Laboratory in Upton, New York have identified a previously unknown phase of matter hidden inside a magnetic compound, one with a paradoxical internal structure that switches between states over an extraordinarily narrow temperature range. The findings appear in the December 31, 2024, edition of Physical Review Letters, describing what the researchers call a new direction for understanding and controlling phase transitions in certain materials. The new phase, dubbed “half ice, half fire,” consists of two opposing populations of electron spins coexisting simultaneously within the same material. One population is highly ordered, referred to as “cold,” while the other is highly disordered, referred to as “hot.” Electron spins are the tiny magnetic…