Critical and tricritical behavior of a selectively diluted triangular Ising antiferromagnet in a field

M. Borovský; M. Žukovič; A. Bobák

doi:10.1016/j.physa.2012.08.016

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arXiv · 1212.5451

Critical and tricritical behavior of a selectively diluted triangular Ising antiferromagnet in a field

M. Borovský·M. Žukovič·A. Bobák

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Abstract

We study a geometrically frustrated triangular Ising antiferromagnet in an external magnetic field which is selectively diluted with nonmagnetic impurities employing an effective-field theory with correlations and Monte Carlo simulations. We focus on the frustration-relieving effects of such a selective dilution on the phase diagram and find that it can lead to rather intricate phase diagrams in the dilution-field parameters space. In particular, in a highly (weakly) diluted system the frustration is greatly (little) relieved and such a system is found to display only the second(first)-order phase transitions at any field. On the other hand, for a wide interval of intermediate dilution values the transition remains second order at low fields but it changes to first order at higher fields and the system displays a tricritical behavior. The existence of the first-order transition in the region of intermediate dilution and high fields is verified by Monte Carlo simulations.

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M. Borovský, M. Žukovič, A. Bobák. 2012-12-21. Critical and tricritical behavior of a selectively diluted triangular Ising antiferromagnet in a field. https://doi.org/10.1016/j.physa.2012.08.016

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