resumo
We explore the thermodynamics of the 2-D Ising model from a random path sampling method. We show how convergence of free energy and magnetization is obtained in a number of sweeps orders of magnitude below the number of total configurations. The effects of external parameters, such as magnetic field (H) and temperature (T) are accounted in a computationally simple way, allowing very detailed (H, T)-dependent calculations. The effects of more complex interactions can also be considered, particularly magnetovolume coupling, which has proven to be difficult to tackle using traditional approaches. We show its effect on magnetic entropy change (magnetocaloric effect) in this microscopic scenario. As magnetic refrigeration technology matures, the microscopic optimization of magnetovolume effects to enhance the magnetocaloric properties may become a valuable tool in the search of new magnetic refrigerants.
palavras-chave
MONTE-CARLO SIMULATIONS; DISORDER
categoria
Engineering; Physics
autores
Amaral, JS; Goncalves, JN; Amaral, VS
nossos autores
João Cunha de Sequeira Amaral
Investigador Auxiliar
João Nuno Santos Gonçalves
Investigador
Vitor Brás Sequeira Amaral
Professor CatedráticoProjectos
Exploring nano-fabrication methods of high coercivity rare-earth free Si-Alnico permanent magnets (EXPL/CTM-NAN/1614/2013)
Centre for Research in Ceramics and Composite Materials - CICECO (LA0011: 2013-2014) (PEst-C/CTM/LA0011/2013)
agradecimentos
This work was supported by FCT Portugal through Project EXPL/CTM-NAN/1614/2013 (FCOMP-01-0124-FEDER-041688) and PEst-C/CTM/LA0011/2013 (FCOMP-01-0124-FEDER-037271) under Grant SFRH/BPD/82059/2011 (J. N. Goncalves) and Grant SFRH/BPD/63942/2009 (J. S. Amaral).