Add 1 Atomic Layer to Get Magnetism

Researchers have uncovered a new twist in magnetism at the nanoscale.

The team at the National University of Singapore made the discovery while growing atomic layers of a manganite—which shows no magnetism—on a substrate crystal of nonmagnetic strontium titanate.

The manganite’s magnetism is switched on abruptly when the number of manganese atomic layers changes from 5 to 6 or more. Researchers suspect an avalanche of electrons from the top surface of the film falls to the bottom, where the electrons are confined near the substrate.

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This shift of electric charge occurs as the manganese atomic layers form atomically charged capacitors leading to the build-up of an electric field—known as “polar catastrophe”—inside the manganite. As a consequence of this charge transfer, the manganite layer switches to a strongly ferromagnetic state.

The team plans to use local electric fields to controllably turn on/off the magnetism of its 5-layer films, and explore potential applications in microwave devices and magnetic recording and computing.

The findings appear in the journal Science. 

Source: National University of Singapore.  Republished from Futurity.org under Creative Commons License 4.0.