Magnetic Construction Set: Unexpected Flexibility of Atomic Layers ⚡ экспресс
Imagine a material with a pattern resembling a woven basket. Scientists created a variant with a distorted structure and discovered that the iron layers in it magnetize at high temperatures, while the rare-earth atoms only at very low ones. This opens the door to understanding how geometry influences magnetic properties. What else do such 'distorted baskets' conceal?
The new magnetic material is structured like a stack of pancakes: in each layer, all atomic 'arrows' point the same way, but the neighboring layer is magnetized in the opposite direction. The pattern of triangles — a kagome lattice — is distorted because some atoms were replaced with germanium dumbbells. Rare-earth atoms display magnetic order only at temperatures around -264°C, for which liquid helium is used. X-ray diffraction (a method developed by Bragg) and spectroscopy allowed scientists to unveil this structure.
Calculations revealed unexpected flexibility: flipping the entire layer requires a prohibitively large energy, while rotating a single chain of atoms inside the layer is easy. This order dramatically reduces entropy — a measure of disorder. This paves the way for controlled creation of magnetic patterns for future quantum devices.
🎯 The word 'kagome' translates from Japanese as 'woven basket' — exactly the pattern of triangles that the atoms form.