Evidence of impurity and boundary effects on magnetic monopole dynamics in spin ice
2013 (English)In: Nature Physics, ISSN 1745-2473, E-ISSN 1745-2481, Vol. 9, no 1, 34-37 p.Article in journal (Refereed) Published
Electrical resistance is a crucial and well-understood property of systems ranging from computer microchips to nerve impulse propagation in the human body. Here we study the motion of magnetic charges in spin ice and find that extra spins inserted in Dy2Ti2O7 trap magnetic monopole excitations and provide the first example of how defects in a spin-ice material obstruct the flow of monopoles-a magnetic version of residual resistance. We measure the time-dependent magnetic relaxation in Dy2Ti2O7 and show that it decays with a stretched exponential followed by a very slow long-time tail. In a Monte Carlo simulation governed by Metropolis dynamics we show that surface effects and a very low level of stuffed spins (0.30%)-magnetic Dy ions substituted for non-magnetic Ti ions-cause these signatures in the relaxation. In addition, we find evidence that the rapidly diverging experimental timescale is due to a temperature-dependent attempt rate proportional to the monopole density.
Place, publisher, year, edition, pages
2013. Vol. 9, no 1, 34-37 p.
Ising Pyrochlore Magnets, Zero-Point Entropy
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-116419DOI: 10.1038/NPHYS2466ISI: 000312635200013ScopusID: 2-s2.0-84871620509OAI: oai:DiVA.org:kth-116419DiVA: diva2:589919
QC 201301212013-01-212013-01-182013-01-21Bibliographically approved