By a News Reporter-Staff News Editor at Physics Week -- Current study results on Applied Physical Science have been published. According to news reporting originating in Cergy Pontoise, France, by VerticalNews journalists, research stated, "We study the effect of perpendicular single-ion anisotropy, -As-z(2), on the ground-state structure and finite-temperature properties of a two-dimensional magnetic nanodot in presence of a dipolar interaction of strength D. By a simulated annealing Monte Carlo method, we show that in the ground state a vortex core perpendicular to the nanodot plane emerges already in the range of moderate anisotropy values above a certain threshold level. In the giant-anisotropy regime the vortex structure is superseded by a stripe domain structure with stripes of alternate domains perpendicular to the surface of the sample."
The news reporters obtained a quote from the research from the University of Cergy, "We have also observed an intermediate stage between the vortex and stripe structures, with satellite regions of tilted nonzero perpendicular magnetization around the core. At finite temperatures, at small A, we show by Monte Carlo simulations that there is a transition from the the in-plane vortex phase to the disordered phase characterized by a peak in the specific heat and the vanishing vortex order parameter. At stronger A, we observe a discontinuous transition with a large latent heat from the in-plane vortex phase to perpendicular stripe ordering phase before a total disordering at higher temperatures."
According to the news reporters, the research concluded: "In the regime of perpendicular stripe domains, namely with giant A, there is no phase transition at finite T: the stripe domains are progressively disordered with increasing T. Finite-size effects are shown and discussed."
For more information on this research see: Magnetic properties of two-dimensional nanodots: Ground state and phase transition. AIP Advances, 2013;3(12):216-228. AIP Advances can be contacted at: Amer Inst Physics, Circulation & Fulfillment Div, 2 Huntington Quadrangle, Ste 1 N O 1, Melville, NY 11747-4501, USA. (American Institute of Physics - www.aip.org/; AIP Advances - aipadvances.aip.org/)
Our news correspondents report that additional information may be obtained by contacting M. Kasperski, Univ Cergy Pontoise, Lab Phys Theor & Modelisat, CNRS, UMR 8089, F-95302 Cergy Pontoise, France. Additional authors for this research include H. Puszkarski, D.T. Hoang and H.T. Diep.
Keywords for this news article include: France, Europe, Cergy Pontoise, Applied Physical Science
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC