Extremely small arrays of magnets with strange and unusual properties can order themselves by increasing entropy. The tendency of physical systems to disorder which is a behaviour that appears to contradict standard thermodynamics, but doesn’t.
The system examined in this work is known as tetris spin ice, it was studied as part of a long-standing collaboration between Nisoli and Peter Schiffer at Yale University with theoretical analysis and simulations led at Los Alamos and experimental work led at Yale. Scientists included other scientists from a number of universities and academic institutions.
Nanomagnet arrays show promise as circuits of logic gates in neuromorphic computing which is a leading-edge computing architecture that closely mimics how the brain works. They also have possible applications in a number of high-frequency devices using “magnonics” that exploit the dynamics of magnetism on the nanoscale.
Entropy is the measure of the state of disorder, randomness or uncertainty in a physical system. A liquid has high entropy because at warm temperatures. Its molecules are free to move around in a random and disordered way.
The molecules calm down and order themselves through interactions to optimize their energy, when liquids are cooled to form solids. They can arrange themselves in a crystal lattice in only a limited number of configurations. This lowers their entropy. Some systems are not so simple. Parts of the system settle in an orderly way.
Tetris spin ice is composed of 2D arrays of very small magnets. These interact but are frustrated. The magnetic pole orientations frustrated in such way that the system retains some order while remaining disordered. At low temperature it decomposes into alternating ordered and disordered stripes.