The Landau--Lifshitz--Bloch equation with spin diffusion: Global strong solution and finite element approximation

Fuente: arXiv
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Main Author: Soenjaya, Agus L.
Format: Preprint
Published: 2026
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author Soenjaya, Agus L.
author_facet Soenjaya, Agus L.
contents The spin-diffusion Landau--Lifshitz--Bloch (SDLLB) system is a nonlinearly coupled system of quasilinear vector-valued PDEs which models the interaction between spin-polarised currents and magnetisation at high temperatures. The aim of this paper is twofold. Firstly, assuming the initial data is sufficiently small, we show the existence of a unique global strong solution to the SDLLB equation in a bounded domain $Ω\subset \mathbb{R}^d$, where $d\leq 3$, thus ensuring well-posedness of the model. Secondly, we propose a decoupled linearised fully-discrete finite element scheme to solve the problem. Despite the strong nonlinearity of the system, the proposed scheme only requires the solution of two completely decoupled linear systems per time-step. Assuming adequate regularity of the exact solution and a certain time-step constraint, we rigorously show that the numerical scheme converges at an optimal rate. Several numerical experiments corroborate our theoretical results.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01668
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Landau--Lifshitz--Bloch equation with spin diffusion: Global strong solution and finite element approximation
Soenjaya, Agus L.
Numerical Analysis
Analysis of PDEs
65M12, 65M60, 35K59, 35Q60
The spin-diffusion Landau--Lifshitz--Bloch (SDLLB) system is a nonlinearly coupled system of quasilinear vector-valued PDEs which models the interaction between spin-polarised currents and magnetisation at high temperatures. The aim of this paper is twofold. Firstly, assuming the initial data is sufficiently small, we show the existence of a unique global strong solution to the SDLLB equation in a bounded domain $Ω\subset \mathbb{R}^d$, where $d\leq 3$, thus ensuring well-posedness of the model. Secondly, we propose a decoupled linearised fully-discrete finite element scheme to solve the problem. Despite the strong nonlinearity of the system, the proposed scheme only requires the solution of two completely decoupled linear systems per time-step. Assuming adequate regularity of the exact solution and a certain time-step constraint, we rigorously show that the numerical scheme converges at an optimal rate. Several numerical experiments corroborate our theoretical results.
title The Landau--Lifshitz--Bloch equation with spin diffusion: Global strong solution and finite element approximation
topic Numerical Analysis
Analysis of PDEs
65M12, 65M60, 35K59, 35Q60
url https://arxiv.org/abs/2604.01668