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arXiv · 1005.5484

Evidence for power-law Griffiths singularities in a layered Heisenberg magnet

Fawaz Hrahsheh·Hatem Barghathi·Priyanka Mohan·Rajesh Narayanan·Thomas Vojta
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Abstract

We study the ferromagnetic phase transition in a randomly layered Heisenberg model. A recent strong-disorder renormalization group approach [Phys. Rev. B 81, 144407 (2010)] predicted that the critical point in this system is of exotic infinite-randomness type and is accompanied by strong power-law Griffiths singularities. Here, we report results of Monte-Carlo simulations that provide numerical evidence in support of these predictions. Specifically, we investigate the finite-size scaling behavior of the magnetic susceptibility which is characterized by a non-universal power-law divergence in the Griffiths phase. In addition, we calculate the time autocorrelation function of the spins. It features a very slow decay in the Griffiths phase, following a non-universal power law in time.

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Fawaz Hrahsheh, Hatem Barghathi, Priyanka Mohan, Rajesh Narayanan, Thomas Vojta. 2010-05-29. Evidence for power-law Griffiths singularities in a layered Heisenberg magnet. https://doi.org/10.1088/1742-6596%2F273%2F1%2F012004

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