Physics got a new spin liquid of quantum octupole ice

Physicists have discovered a new type of quantum spin liquid, which is based on previously predicted exotic state of quantum spin ice octupole magnetic moments. The opening is made in connection Ce2Sn2O7 structure of the mineral pyrochlore, the article published in the journal Nature Physics.

The most common state of the magnetic substances, especially at low temperatures, is the magnetic ordering. When magnetic ordering all spins in the substance are directed in certain directions and it is very difficult to change direction. This is due to the fact that they are rigidly connected together by the exchange interaction, which causes neighboring spins to line up against each other at a certain angle. The figure spins in the ordered substances can be simple (all spins in one direction) and complex (e.g., spiral). But all these pictures have in common is that they are periodic. Therefore, the magnetic ordering is also called the far magnetic order, as it determines the relative direction of the spins in the whole matter. Magnetic ordering of the required properties, for example, ferromagnets, which are known for their ability to adhere to the gland and to each other.

A much more rare state is a quantum spin liquid. In such a liquid (in its state of aggregation the substance is a solid) at low temperature is not observed magnetic ordering, but by the collective entangled state of the spins. The lack of magnetic ordering means that the spins are not fixed even at the lowest temperatures they can still turn over or turn. But, since the spins linked a strong exchange interaction, all their movements are aligned even over large distances and constitute a single movable quantum system. This coherence (entanglement) can be used, for example, to build a fault tolerant quantum computer. Read more about spin liquids and quantum computers can be read in our materials Quantum alphabet: “Spin liquid” and “Quantum computer”.

There are other unusual disordered magnetic state. For example, spin ice, in which spins are “frozen” in a particular, but a chaotic state without long-range order. However, it seems chaotic at first glance. On closer examination it appears that the neighboring spins in such a substance arranged in a certain rule, that is, there is short-range magnetic order. For some substances, for example, with the structure of the mineral pyrochlore, these rules are similar to the behavior of water molecules in crystals of ordinary ice.

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