Research in Applied Mathematics
vol. 1 (2017), Article ID 101264, 16 pages
doi:10.11131/2017/101264
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Research Article
A Finite Difference Scheme for
the Time-Fractional Landau-Lifshitz-Bloch
Equation
C. Ayouch
1
, E. H. Essoufi
1
, and M. Tilioua
2
1
Laboratoire MISI, FST Settat, Univ. Hassan I, 26000 Settat, Morocco
2
M2I Laboratory, MAMCS Group, FST Errachidia, Univ. Moulay Ismaïl, P.O. Box 509,
Boutalamine, 52000 Errachidia, Morocco
Abstract. In this paper, we study a finite difference scheme for temporal discretization of the
time-fractional Landau-Lifshitz-Bloch equation, such as the fractional time derivative of order
is taken in the sense of Caputo. An existence result is established for the semi-discrete problem
by Schaefer’s fixed point theorem. Stability and error analysis are then provided, showing that
the temporal accuracy is of order 2−.
Keywords: Landau-Lifshitz-Bloch equation, finite difference method, fractional differential
equations, Schaefer’s fixed point, existence, stability, error analysis
Mathematics Subject Classification: 78A25, 35Q60, 35B40
1. Introduction
The conventional Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation is a grand
master equation that provides quantitative predictions on magnetic structure and magnetiza-
tion dynamics of ferromagnets at low temperatures. At high temperatures, however, the LLG
equation fails to describe the longitudinal relaxation and thus it is necessary to extend the
LL equation. In particular, it is desirable to obtain a similarly effective equation, which is
capable of quantitatively computing magnetization dynamics at high temperatures in real time.
Such extension is not only theoretically interesting but also technologically relevant. For high
temperatures the LLG equation must be replaced by a more thermodynamically consistent
approach such as the Landau-Lifshitz-Bloch (LLB) equation [3]. The LLB equation essentially
interpolates between the LLG equation at low temperatures and the Ginzburg-Landau theory of
phase transitions. It is valid not only below but also above the Curie temperature
. An impor-
tant property of the LLB equation is that the magnetization magnitude is no longer conserved
but is a dynamical variable [4]. The spin polarization vector (, ), where =
0
, and is
magnetization vector and
0
is the saturation magnetization value at =0. For Ω⊂ℝ
,≥1,
satisfies the following LLB equation
= ×
eff
() +
1
||
2
(
⋅
eff
()
)
−
2
||
2
×
(
×
eff
()
)
, (1)
where >0 is the gyromagnetic ratio, the symbol × denotes the vector cross product in ℝ
3
,
1
and
2
are the longitudinal and transverse damping parameters, respectively.
How to cite this article: C. Ayouch, E. H. Essoufi, and M. Tilioua, “A Finite Difference Scheme for the Time-Fractional Landau-
Lifshitz-Bloch Equation,” Research in Applied Mathematics, vol. 1, Article ID 101264, 16 pages, 2017. doi:10.11131/2017/101264
Page 1
Corresponding Author
M. Tilioua
tilioua@melix.org
Editor
Jianlong Qiu
Dates
Received 14 November 2016
Accepted 24 February 2017
Copyright © 2017 C. Ayouch
et al. This is an open access
article distributed under the
Creative Commons
Attribution License, which
permits unrestricted use,
distribution, and reproduction
in any medium, provided the
original work is properly
cited.