Publication Date:
2009-09-05
Description:
Sources of magnetic fields-magnetic monopoles-have so far proven elusive as elementary particles. Condensed-matter physicists have recently proposed several scenarios of emergent quasiparticles resembling monopoles. A particularly simple proposition pertains to spin ice on the highly frustrated pyrochlore lattice. The spin-ice state is argued to be well described by networks of aligned dipoles resembling solenoidal tubes-classical, and observable, versions of a Dirac string. Where these tubes end, the resulting defects look like magnetic monopoles. We demonstrated, by diffuse neutron scattering, the presence of such strings in the spin ice dysprosium titanate (Dy2Ti2O7). This is achieved by applying a symmetry-breaking magnetic field with which we can manipulate the density and orientation of the strings. In turn, heat capacity is described by a gas of magnetic monopoles interacting via a magnetic Coulomb interaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Morris, D J P -- Tennant, D A -- Grigera, S A -- Klemke, B -- Castelnovo, C -- Moessner, R -- Czternasty, C -- Meissner, M -- Rule, K C -- Hoffmann, J-U -- Kiefer, K -- Gerischer, S -- Slobinsky, D -- Perry, R S -- New York, N.Y. -- Science. 2009 Oct 16;326(5951):411-4. doi: 10.1126/science.1178868. Epub 2009 Sep 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Helmholtz-Zentrum Berlin fur Materialien und Energie, Glienicker Str. 100, D-14109 Berlin, Germany. jonathan.morris@helmholtz-berlin.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19729617" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
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Medicine
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Natural Sciences in General
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Physics
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