A Spin-Lattice Dynamics Simulation Program Version 1.0

Pui-Wai (Leo) Ma, S. L. Dudarev

Culham Centre for Fusion Energy, UK Atomic Energy Authority, Abingdon, Oxfordshire OX14 3DB, United Kingdom

C. H. Woo

Department of Physics and Materials Science, The City University of Hong Kong, Kowloon, Hong Kong SAR, China

License Copyright (C) 2015-2018 Culham Centre for Fusion Energy

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Introduction SPILADY (pronounced as [spileidi]) is a computer program written at Culham Centre for Fusion Energy, Oxfordshire OX14 3DB, United Kingdom, from March 2014 to July 2015. It is a spin-lattice dynamics code intended to serve as an introductory computer simulation tool for undergraduate students, scientists, researchers, and interested members of the public familiar with molecular dynamics.

Reference material Papers, giving a fairly detailed description of the spin-lattice dynamics simulation methodology and explaining the fundamentals of the method, are listed below. A SPILADY user is advised to refer to the material given in the papers when performing simulations, as the papers contain answers to questions that we are not able to cover in detail in this manual.

1. The basics of spin-lattice dynamics algorithm:

“Large-scale simulation of the spin-lattice dynamics in ferromagnetic iron" Pui-Wai Ma, C. H. Woo, and S. L. Dudarev, Phys. Rev. B 78. 024434 (2008)

2. Spin-lattice-electron dynamics / molecular-electron dynamics:

“Spin-lattice-electron dynamics simulations of magnetic materials" Pui-Wai Ma, S. L. Dudarev, and C. H. Woo, Phys. Rev. B, 85, 184301 (2012)

3. Local collective motion of atoms and electrons:

“Spin-lattice-electron dynamics simulations of magnetic materials"
Pui-Wai Ma, S. L. Dudarev, and C. H. Woo, Phys. Rev. B, 85, 184301 (2012)

4. Fluctuation-dissipation Langevin spin dynamics:

“Langevin spin dynamics"
Pui-Wai Ma and S. L. Dudarev, Phys. Rev. B 83, 134418 (2011)

5. Longitudinal magnetic fluctuations:

“Longitudinal magnetic fluctuations in Langevin spin dynamics"
Pui-Wai Ma and S. L. Dudarev, Phys. Rev B 86, 054416 (2012)

6. How to compute the kinematic temperature of atoms and temperature of fluctuating magnetic moments:

“Temperature for a dynamic spin ensemble"
Pui-Wai Ma, S. L. Dudarev, A. A. Semenov, and C. H. Woo, Phys. Rev. E 82, 031111 (2010)

7. A parallel algorithm for spin-lattice dynamics simulations:

“Parallel algorithm for spin and spin-lattice dynamics simulations"
Pui-Wai Ma and C. H. Woo, Phys. Rev. E 79, 046703 (2009)

8. A paper describing this computer code (SPILADY):

“SPILADY: A Parallel GPU and CPU Code for Spin-Lattice Dynamics” Pui-Wai Ma and S. L. Dudarev, Computer Physics Communications, 207, 350-361 (2016)

Acknowledgement The development and release of this SPILADY program has been made possible through the support provided by a EUROfusion Enabling Research grant WP14-ER-01/CCFE-02 "Dynamic Evolution of Non-Equilibrium High-Temperature Thermodynamic Properties of Magnetic Metals". The work was carried out within the framework of EUROfusion Consortium and has received funding from Euratom research and training programme 2014-2018 under grant agreement No 633053 and from the RCUK Energy Programme [grant number EP/I501045]. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Contact For more information on SPILADY please email [email protected].