Current browse context:
math.NA
Change to browse by:
References & Citations
Condensed Matter > Mesoscale and Nanoscale Physics
Title: Micromagnetic simulations of the size dependence of the Curie temperature in ferromagnetic nanowires and nanolayers
(Submitted on 11 Jan 2024 (v1), last revised 25 Apr 2024 (this version, v2))
Abstract: We solve the Landau-Lifshitz-Gilbert equation in the finite-temperature regime, where thermal fluctuations are modeled by a random magnetic field whose variance is proportional to the temperature. By rescaling the temperature proportionally to the computational cell size $\Delta x$ ($T \to T\,\Delta x/a_{\text{eff}}$, where $a_{\text{eff}}$ is the lattice constant) [M. B. Hahn, J. Phys. Comm., 3:075009, 2019], we obtain Curie temperatures $T_{\text{C}}$ that are in line with the experimental values for cobalt, iron and nickel. For finite-sized objects such as nanowires (1D) and nanolayers (2D), the Curie temperature varies with the smallest size $d$ of the system. We show that the difference between the computed finite-size $T_{\text{C}}$ and the bulk $T_{\text{C}}$ follows a power-law of the type: $(\xi_0/d)^\lambda$, where $\xi_0$ is the correlation length at zero temperature, and $\lambda$ is a critical exponent. We obtain values of $\xi_0$ in the nanometer range, also in accordance with other simulations and experiments. The computed critical exponent is close to $\lambda=2$ for all considered materials and geometries. This is the expected result for a mean-field approach, but slightly larger than the values observed experimentally.
Submission history
From: Clémentine Courtès [view email][v1] Thu, 11 Jan 2024 07:57:14 GMT (2196kb,D)
[v2] Thu, 25 Apr 2024 10:10:46 GMT (2203kb,D)
Link back to: arXiv, form interface, contact.