Fragmentation of magnetism in dipolar spin ice
Few cases exist where a system remains disordered as a gas or a liquid, even at the lowest temperatures accessible experimentally. Systems that simultaneously exhibit different order states are even rarer. Such a phase, “liquid” and “solid” at the same time, has been recently observed in a magnetic metamaterial, artificial spin ice.
B. Canals et al., Nat. Comm. 7, 11446 (2016);
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We demonstrate the magnetic equivalent of both liquid and crystalline phases in a system which is not phase separated. This is a specially designed magnetic metamaterial called spin ice. Its peculiar magnetic properties were characterized at the Nanospectroscopy beamline of Elettra using x-ray circular dichroism photoemission electron microscopy. When imaged in real space, the magnetic configuration is essentially disordered. However, when visualized in reciprocal space, a coexistence of Bragg peaks and a diffuse background show up , thus indicating that the system is both ordered and disordered. This is not a coexistence of two out-of-equilibrium phases, but a state of matter that is both liquid and solid, everywhere in the lattice, at thermodynamic equilibrium. Interestingly, |
A detailed analysis of the magnetic configuration reveals that the system acts as if each individual nanomagnet of the lattice was split into two separate components. Retrieve article
Fragmentation of magnetism in artificial kagome dipolar spin ice |
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