Sala, G., Castelnovo, C., Moessner, R., sondhi, S., Kitagawa, K., Takigawa, M., Higashinaka, R. and Maeno, Y. (2012) A field trip through spin ice. Physical Review Letters
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Fractionalisation -- the breaking up of an apparently indivisible microscopic degree of freedom -- is one of the most counterintuitive phenomena in many-body physics. Here we study its most fundamental manifestation in spin ice, the only known fractionalised magnetic compound in 3D: we directly visualise the $1/r^2$ magnetic Coulomb field of monopoles which emerge as the atomic magnetic dipoles fractionalise. We analyse the internal magnetic field distribution, relevant for local experimental probes. In particular, we present new zero-field NMR measurements which exhibit excellent agreement with the calculated lineshapes, noting that this experimental technique can in principle measure directly the monopole density in spin ice. The distribution of field strengths is captured by a simple analytical form which exhibits a low density of low-field sites---in apparent disagreement with reported $\mu$SR results. Counterintuitively, the density of low-field locations decreases as the local ferromagnetic correlations imposed by the ice rules weaken.
This is a Draft version This version's date is: 2012 This item is not peer reviewed
https://repository.royalholloway.ac.uk/items/3276598a-b9b0-b506-82cf-f479c2a32035/1/
Deposited by Research Information System (atira) on 29-Aug-2012 in Royal Holloway Research Online.Last modified on 29-Aug-2012
(7 pages; 6 figures)