Thermal stability of magnetic states in submicron magnetic islands

Liashko, S Y; Lobanov, I. S.; Uzdin, V. M.; Jónsson, Hannes

doi:10.17586/2220-8054-2017-8-5-572-578

Cited by 3 publications

(6 citation statements)

References 39 publications

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“…The calculations are based on an extended Stoner-Wohlfarth model that takes into account thermal fluctuations [16]. This model was recently used to analyze remagnetization in elements of kagome spin ice [17].…”

Section: Modelmentioning

confidence: 99%

“…It is chosen in the same way as in ref. [16] for consistency. In the present case, the magnetic moment entering the model represents a critical nucleus for the remagnetization transition, not the total magnetic moment of the island.…”

Section: Modelmentioning

confidence: 99%

“…The parameters V and K 1 are treated as adjustable model parameters. For an applied magnetic field, H, pointing in the direction of the out-of-plane anisotropy axis the extended Stoner-Wohlfarth model gives an analytical expression for the rate of magnetization reversals [16]:…”

Section: Modelmentioning

confidence: 99%

“…In this article, we present calculations using an extended Stoner-Wohlfarth model [16] where the effect of thermal activation has been added and analyze the experimental measurements reported by de Vries et al An analytical expression for the remagnetization rate, both pre-exponential factor, and activation energy is used to evaluate the SFD for both weak and strong islands. By adjusting two parameters in the model, the effective anisotropy constant and the nucleation volume, to reproduce the measured SFD peak positions, the full shape of the SFD at both 10 K and 300 K is found to be in close agreement with the experiments, without the need to vary the values of the parameters with temperature.…”

Section: Introductionmentioning

confidence: 99%

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Calculations of switching field and energy barrier for magnetic islands with perpendicular anisotropy

Liashko¹,

Jónsson²,

Uzdin³

2017

Nanosystems: Phys. Chem. Math.

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Calculations of the magnetic field required to reverse the magnetization of islands with out-of-plane anisotropy are carried out using a model describing nucleation followed by rapid domain wall motion. The calculations are based on an extension of the Stoner-Wohlfarth model where thermal activation is taken into account as well as the applied magnetic field. The calculated switching field distribution (SFD) is compared with recently reported experimental measurements of de Vries et al. [New J. Phys. 19, 093019 (2017)] on circular 220 nm CoPt islands.The measured results can be closely reproduced by choosing appropriate values of two parameters, the nucleation volume, and the effective anisotropy. Both the position of SDF peaks and their width at high and low temperature, 300 K and 10 K, are amply described using the same set of parameter values for a given island, while there is a large difference between islands with weak and strong magnetic anisotropies. There is no need to introduce the temperature dependence of the activation energy at zero field. This is in contrast with the estimates obtained from the so-called diamond model used by de Vries et al. in their data analysis where multiple adjustable parameters are introduced, and a three-to fourfold change in the zero field activation energy is invoked.

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Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calculations of switching field and energy barrier for magnetic islands with perpendicular anisotropy

Liashko¹,

Jónsson²,

Uzdin³

2017

Nanosystems: Phys. Chem. Math.

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“…The mechanism of thermally assisted transitions in such systems can be evaluated using the geodesic nudged elastic band (GNEB) method [18] where the activation energy is obtained as the energy rise along the minimum energy path for the transition. The pre-exponential in the Arrhenius rate expression can be estimated from harmonic transition state theory [19][20][21] as has been demonstrated for isolated islands [22] as well as elements of kagome spin ice [23]. When the islands are not too large, the magnetization can be in a single domain state and described by a single vector, the macrospin.…”

Section: Introductionmentioning

confidence: 99%

Models of the energy landscape for an element of shakti spin ice

Arnalds¹,

Liashko²,

Bessarab³

et al. 2018

Nanosystems: Phys. Chem. Math.

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Micromagnetic calculations are compared with faster model calculations of interacting nanoscopic magnetic islands representing an element of a shakti spin ice lattice. Several pathways for transitions between equivalent ground states are studied. The model calculations describe the interaction between the islands either with the point dipole approximation, or with a dumbbell approximation where the distance between the two poles is optimized to match the micromagnetic results. The closest agreement in the energy of both local minima as well as transition state configurations where one macrospin has rotated by 90 • is obtained with a dumbbell model where the distance between the poles is ca. 20 % smaller than the island length.

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