Metastability for the Blume-Capel model with distribution of magnetic anisotropy using different dynamics

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dc.contributorVirginia Techen
dc.contributor.authorYamamoto, Y.en
dc.contributor.authorPark, K.en
dc.contributor.departmentPhysicsen
dc.date.accessed2013-12-17en
dc.date.accessioned2014-01-17T13:41:35Zen
dc.date.available2014-01-17T13:41:35Zen
dc.date.issued2013-07-11en
dc.description.abstractWe investigate the relaxation time of magnetization or the lifetime of the metastable state for a spin S = 1 square-lattice ferromagnetic Blume-Capel model with distribution of magnetic anisotropy (with small variances), using two different dynamics such as Glauber and phonon-assisted dynamics. At each lattice site, the Blume-Capel model allows three spin projections (+1, 0, -1) and a site-dependent magnetic anisotropy parameter. For each dynamic, we examine the low-temperature lifetime in two dynamic regions with different sizes of the critical droplet and at the boundary between the regions, within the single-droplet regime. We compute the average lifetime of the metastable state for a fixed lattice size, using both kinetic Monte Carlo simulations and the absorbing Markov chains method in the zero-temperature limit. We find that for both dynamics the lifetime obeys a modified Arrhenius-like law, where the energy barrier of the metastable state depends on the temperature and standard deviation of the distribution of magnetic anisotropy for a given field and magnetic anisotropy and that an explicit form of this dependence differs in different dynamic regions for different dynamics. Interestingly, the phonon-assisted dynamic prevents transitions between degenerate states, which results in a large increase in the energy barrier at the region boundary compared to that for the Glauber dynamic. However, the introduction of a small distribution of magnetic anisotropy allows the spin system to relax via lower-energy pathways such that the energy barrier greatly decreases. In addition, for the phonon-assisted dynamic, even the prefactor of the lifetime is substantially reduced for a broad distribution of magnetic anisotropy in both regions considered, in contrast to the Glauber dynamic. Our findings show that overall the phonon-assisted dynamic is more significantly affected by the distribution of magnetic anisotropy than the Glauber dynamic.en
dc.description.sponsorshipNSF DMR-0804665, DMR-1206354en
dc.format.mimetypeapplication/pdfen
dc.identifier.citationYamamoto, Yoh ; Park, Kyungwha, Jul 11, 2013. "Metastability for the Blume-Capel model with distribution of magnetic anisotropy using different dynamics," PHYSICAL REVIEW E 88(1): 012110. DOI: 10.1103/PhysRevE.88.012110en
dc.identifier.doihttps://doi.org/10.1103/PhysRevE.88.012110en
dc.identifier.issn1539-3755en
dc.identifier.urihttp://hdl.handle.net/10919/24902en
dc.identifier.urlhttp://link.aps.org/doi/10.1103/PhysRevE.88.012110en
dc.language.isoenen
dc.publisherAmerican Physical Societyen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectkinetic ising-modelen
dc.subjectfept nanoparticlesen
dc.subjectsystemsen
dc.subjectfielden
dc.subjectspinen
dc.subjectrelaxationen
dc.subjectnucleationen
dc.subjectdependenceen
dc.subjectconstanten
dc.subjectlatticeen
dc.subjectPhysicsen
dc.titleMetastability for the Blume-Capel model with distribution of magnetic anisotropy using different dynamicsen
dc.title.serialPhysical Review Een
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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