Origin of the double shifted hysteresis loops in thin ferromagnetic films with bias fields

Yang, Jyh‐Shinn; Chang, Ching‐Ray; Lai, Chih‐Huang

doi:10.1016/s0304-8853(01)00520-0

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…The dipolar field dictates the hysteresis behaviour for µ o H/H K > 0.5, resulting in a spontaneous orientation transition of magnetization. These results are in perfect agreement with the work of Yang et al [49]. It is also clearly evident that there is a strong effect of disorder on hysteresis response.…”

Section: Simulations Resultssupporting

confidence: 93%

Controlling Dipolar Interaction Effect in Two-Dimensional Magnetic Nanostructures

Anand

2021

Preprint

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We investigate the dependence of magnetic properties on the out-of-plane disorder strength ∆, dipolar interaction strength h d in two-dimensional (l x × l y ) ensembles of nanoparticles using numerical simulations. Such positional defects are redundantly observed in experiments. The superparamagnetic character is dominant with negligible and weak interaction strength h d , irrespective of ∆ and aspect ratio of the system A r = l y /l x . The double-loop hysteresis curve, characteristics of antiferromagnetic coupling dominance, emerges with large h d and ∆(%) ≤ 5 in the square-like nanoparticles' assays. Remarkably, the dipolar interaction of sufficient strength drives the magnetic order from antiferromagnetic to ferromagnetic with large ∆ and A r ≤ 4.0, resulting in an enhancement in the hysteresis loop area. On the other hand, the ferromagnetic coupling gets increased with h d in systems with huge A r . Consequently, the hysteresis loop is enormous, even with moderate h d . The variation of the coercive field µ o H c , remanence M r , and amount of heat released E H (due to the hysteresis) with these parameters also suggests the transformation of nature dipolar interaction. They are significant even with large h d and smaller A r , indicating the antiferromagnetic coupling dominance. Interestingly, there is an enhancement in these with ∆ and large h d due to ferromagnetic interaction. Notably, they are very significant even with moderate h d in the highly anisotropic system and external field along the long axis of the sample. These results could help the experimentalist in explaining the unusual hysteresis characteristics observed in such systems and should also be beneficial in diverse applications such as data storage, magnetic hyperthermia, etc.

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Section: Simulations Resultssupporting

confidence: 93%

Controlling Dipolar Interaction Effect in Two-Dimensional Magnetic Nanostructures

Anand

2021

Preprint

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“…The dipolar interaction dominates the hysteresis for µ o H/H K > 0.5, resulting in a spontaneous transition in magnetization orientation. Yang et al also observed similar double loop hysteresis in the thin-film[46]. Our observations are in excellent agreement with them.…”

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confidence: 92%

Anisotropic Effect of Dipolar Interaction in Ordered Ensembles of Nanoparticles

Anand

2021

Preprint

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We implement extensive computer simulations to investigate the hysteresis characteristics in the ordered arrays (l x × l y ) of magnetic nanoparticles as a function of aspect ratio A r = l y /l x , dipolar interaction strength h d , and external magnetic field directions. We have considered the aligned anisotropy case, α is the orientational angle. It provides an elegant en route to unearth the explicit role of anisotropy and dipolar interaction on the hysteresis response in such a versatile system. The superparamagnetic character is dominant with weak dipolar interaction (h d ≤ 0.2), resulting in the minimal hysteresis loop area. Remarkably, the double-loop hysteresis emerges even with moderate interaction strength (h d ≈ 0.4), reminiscent of antiferromagnetic coupling. These features are strongly dependent on α and A r . Interestingly, the hysteresis loop area increases with h d , provided A r is enormous, and the external magnetic field is along the y-direction. The coercive field µ o H c , remanent magnetization M r , and the heat dissipation E H also depend strongly on these parameters. Irrespective of the external field direction and weak dipolar interaction (h d ≤ 0.4), there is an increase in µ o H c with h d for a fixed α and A r ≤ 4.0. The dipolar interaction also elevates M r as long as A r is huge and the field is along the y-direction. E H is minimal for negligible and weak dipolar interaction, irrespective of A r , α, and the field directions. Notably, the magnetic interaction enhances E H if A r is enormous and the magnetic field is along the long axis of the system. These results are beneficial in various applications of interest such as digital data storage, spintronics, etc.

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Anisotropic effect of dipolar interaction in ordered ensembles of nanoparticles

Anand

2022

J Nanopart Res

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Origin of the double shifted hysteresis loops in thin ferromagnetic films with bias fields

Cited by 7 publications

References 7 publications

Controlling Dipolar Interaction Effect in Two-Dimensional Magnetic Nanostructures

Controlling Dipolar Interaction Effect in Two-Dimensional Magnetic Nanostructures

Anisotropic Effect of Dipolar Interaction in Ordered Ensembles of Nanoparticles

Anisotropic effect of dipolar interaction in ordered ensembles of nanoparticles

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