Monte Carlo simulations on rare-earth Holmium ultra-thin films - Condensed Matter > Statistical MechanicsReport as inadecuate




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Abstract: Motivated by recent experimental results in ultra-thin helimagnetic Holmiumfilms, we have performed an extensive classical Monte Carlo simulation of filmsof different thickness, assuming a Hamiltonian with six inter-layer exchangeconstants. Both magnetic structure and critical properties have been analyzed.For n>16 n being the number of spin layers in the film a correct bulk limitis reached, while for lower n the film properties are clearly affected by thestrong competition among the helical pitch and the surface effects, whichinvolve the majority of the spin layers: In the thickness range n=9-16 threedifferent magnetic phases emerge, with the high-temperature, disordered,paramagnetic phase and the low-temperature, long-range ordered one separated byan intriguing intermediate-temperature block phase, where outer ordered layerscoexist with some inner, disordered ones. The phase transition of these innerlayers displays the signatures of a Kosterlitz-Thouless one. Finally, for n<~7the film collapse once and for all to a quasi-collinear order. A comparison ofour Monte Carlo simulation outcomes with available experimental data is alsoproposed, and further experimental investigations are suggested.



Author: Fabio Cinti, Alessandro Cuccoli, Angelo Rettori

Source: https://arxiv.org/







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