A few months ago, a team of scientists from the National Institute of Standards and Technology (NIST) reported something surprising about a 2D magnetic material: Behavior that had long been presumed to be due to vibrations in the lattice – the internal structure of the atoms in the material itself – is actually due to a wave of spin oscillations.
This week, the same group describes another surprise finding in a different 2D magnetic material: Behavior presumed to be due to a wave of spin oscillations is actually due to vibrations in the lattice.
The work, published in Nature Communications, is further evidence that the NIST team’s unique experimental capabilities play a pivotal role as an investigative tool for scientists studying these 2D magnets.
Credit: Sean Kelley/NIST
Vibrations in a lattice: This is an illustration of quantized lattice vibrations in a material, where the word ‘quantized’ is used to mean that only certain frequencies of vibrations are allowed. In this animation, you can see how this vibration propagates through the structure of a one-dimensional (1D) chain of atoms, with some atoms getting closer to each other, then farther away, as the material vibrates.
Waves of spin oscillations involve changes to a quantum property of atoms called spin; the feature that makes magnets magnetic. If you think of each atom as being a compass, then spin is (metaphorically) the needle of the compass. In this metaphor, however, the spin can point both north (up) and south (down). In some materials, spin can “flip” from one metaphorical direction to another.
The experiment employed Raman spectroscopy, a technique that probes a sample with laser light and then measures how that light is scattered by the sample. This can reveal information about a 2D material suc ..
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