Effects of random fields on the reversal of magnetisation of Ising ferromagnet

Naskar, Moumita; Acharyya, Muktish

doi:10.1016/j.physa.2020.124583

Cited by 11 publications

(5 citation statements)

References 32 publications

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“…According to the Avrami's law [7] the logarithm of the metastable volume fraction in a ddimensional Ising system decays as ∼ t d+1 close to T c . This behavior has already been verified in the two-dimensional random-field Ising model [5] and the spin-1 Blume-Capel model [6].…”

Section: Numerical Resultssupporting

confidence: 55%

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Metastable behavior of the spin-s Ising and Blume-Capel ferromagnets: A Monte Carlo study

Naskar,

Acharyya,

Vatansever

et al. 2021

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We present an extensive Monte Carlo investigation of the metastable lifetime through the reversal of the magnetization of the spin-s Ising and Blume-Capel models, where s = {1/2, 1, 3/2, 2, 5/2, 3, 7/2}. The mean metastable lifetime (or reversal time) is studied as a function of the applied magnetic field and for both models is found to obey the Becker-Döring theory, as was initially developed for the case of the s = 1/2 Ising ferromagnet within the classical nucleation theory. We have also studied the decay of the metastable volume fraction which nicely follows Avrami's law for all values of s and for both models. For the case of the Blume-Capel model, the integral behavior of the mean metastable lifetime as function of the temperature (T ) and single-ion anisotropy (∆) shows a monotonic variation of the surface (reversal surface) in a three-dimensional plot. Interestingly, the reversal surface appears to be insensitive to the T − ∆ phase boundary of the ferromagnetic-paramagnetic transition of the Blume-Capel ferromagnet.

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Section: Numerical Resultssupporting

confidence: 55%

“…In particular, the effects of a random magnetic field were investigated in Ref. [5], where the cut-off value of the random field was predicted to deviate from the Becker-Döring theory. The role of a uniform anisotropy in the metastability of the spin-1 Blume-Capel ferromagnet was studied in Ref.…”

Section: Introductionmentioning

confidence: 99%

Metastable behavior of the spin-s Ising and Blume-Capel ferromagnets: A Monte Carlo study

Naskar,

Acharyya,

Vatansever

et al. 2021

Preprint

Self Cite

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“…The heat assisted reversal has been studied [12] by Monte Carlo simulation of ultrathin films. The effects of randomly quenched disorder (random field) on the reversal has been reported [13] recently in Ising ferromagnets. The effects of gradient of field [14] and gradient of temperature [15] in the reversal of Ising ferromagnet has also been studied by Monte Carlo (MC) simulation.…”

Section: Introductionmentioning

confidence: 98%

Competitive metastable behaviours of surface and bulk in Ising ferromagnet

Naskar,

Acharyya

2021

Preprint

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The reversal of magnetisation has been studied in a three dimensional Ising ferromagnet by Monte Carlo simulation with Metropolis single spin flip random updating scheme. The outer layers are considered as surface. The surface interacts with core with a relative ferromagnetic interaction strength. The times of reversal of the surface and that of bulk were found to be different for different values of relative interaction strength. For weaker relative strength surface reversal was found to be faster than that of bulk and vice versa for stronger relative interaction strength. A critical value (R c ) of relative interaction strength provides same time of reversal of surface and bulk. This critical relative interaction strength was found to be a function of the temperature (T ) and applied magnetic field (h). The scaling relation R c ∼ h −β f (T h α ), where, α = 0.23 ± 0.01 and β − 0.06 ± 0.01, was found numerically by the method of data collapse. The metastable volume fractions, for both surface and bulk, were found to follow the Avrami's law. The critical relative interaction strength (R c ) has been found to decrease in an exponential (e bx −1.5 ) manner with the system size (L).

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“…All these open fundamental aspects are addressed here so our understanding of metastable phenomena in a random environment is rather limited-see Refs. [12,13] for some particular exceptions. In the present paper, we make one step forward in this direction by studying via Monte Carlo simulations the three-dimensional anisotropic classical Heisenberg ferromagnet with the disorder, generated by a set of random anisotropy distributions.…”

Section: Introductionmentioning

confidence: 99%

Disorder effects on the metastability of classical Heisenberg ferromagnets

et al. 2023

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In the present paper, we investigate the effects of disorder on the reversal time (τ ) of classical anisotropic Heisenberg ferromagnets in three dimensions by means of Monte Carlo simulations. Starting from the pure system, our analysis suggests that τ increases with increasing anisotropy strength. On the other hand, for the case of randomly distributed anisotropy, generated from various statistical distributions, a set of results is obtained: (i) For both bimodal and uniform distributions, the variation of τ with the strength of anisotropy strongly depends on temperature. (ii) At lower temperatures, the decrement in τ with increasing width of the distribution is more prominent. (iii) For the case of normally distributed anisotropy, the variation of τ with the width of the distribution is nonmonotonic, featuring a minimum value that decays exponentially with the temperature. Finally, we elaborate on the joint effect of longitudinal (h z ) and transverse (h x ) fields on τ , which appear to obey a scaling behavior of the form τ h n z ∼ f (h x ).

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Effects of random fields on the reversal of magnetisation of Ising ferromagnet

Cited by 11 publications

References 32 publications

Metastable behavior of the spin-s Ising and Blume-Capel ferromagnets: A Monte Carlo study

Metastable behavior of the spin-s Ising and Blume-Capel ferromagnets: A Monte Carlo study

Competitive metastable behaviours of surface and bulk in Ising ferromagnet

Disorder effects on the metastability of classical Heisenberg ferromagnets

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