Juan Carlos Andresen, Creighton K. Thomas, Helmut G. Katzgraber, Moshe Schechter
We study the interplay between ferromagnetic and spin-glass phases in magnetic systems such as LiHo_xY_{1-x}F_4 theoretically, as well as using numerical simulations of a three-dimensional diluted long-range dipolar Ising model with competing interactions in the presence of a random field. Our results suggest the existence of a novel disordering mechanism of the ferromagnetic phase due to the underlying spin-glass phase when a random field is applied. We numerically compute the zero-temperature phase boundary between the quasi-spin-glass and ferromagnetic phases as a function of the Ho concentration and random-field strength, and explain the peculiar linear dependence of the critical temperature on the strength of the random field found in recent experiments by Silevitch et a. [Nature 448, 567 (2007)] on the LiHo_xY_{1-x}F_4 compound.
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http://arxiv.org/abs/1205.1572
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