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arXiv · 1210.8137

NMR relaxation in spin ice due to diffusing emergent monopoles

Christopher L. Henley
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Abstract

At low temperatures, spin dynamics in ideal spin ice is due mainly to dilute, thermally excited magnetic monopole excitations. I consider how these will affect the dynamics of a nuclear spin (the same theory applies to muon spin resonance if implanted muons do not diffuse). Up to the time scale for nearby monopoles to be rearranged, a stretched-exponential form of the relaxation functions is expected. I work out the expected exponent in that exponential and the formulas for the $T_1$ (longitudinal) and $T_2$ (dephasing) relaxations, as a function of the monopole density. Experimental NMR is incompatible with the predictions and I suggest is due to magnetic impurities.

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Christopher L. Henley. 2012-10-30. NMR relaxation in spin ice due to diffusing emergent monopoles. https://arxiv.org/abs/1210.8137

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