Presentation Information
[P2-13]Modelling of hard magnetic materials from density functional theory
*Miroslaw Werwinski1, Wojciech Marciniak1,2,3, Justyn Snarski-Adamski1, Joanna Marciniak1,3, Justyna Rychły-Gruszecka1 (1. Institute of Molecular Physics, Polish Academy of Sciences (Poland), 2. Faculty of Materials Engineering and Technical Physics, Poznan University of Technology (Poland), 3. Department of Physics and Astronomy, Uppsala University (Sweden))
Keywords:
density functional theory,magnetocrystalline anisotropy energy,Curie temperature,hard magnetic alloys,virtual crystall approximation
Magnetization, Curie temperature, and magnetocrystalline anisotropy energy - the three characteristic intrinsic properties of magnetically hard materials - are available from density functional theory (DFT) calculations. In this presentation, I will discuss the possibilities and limitations of determining the above parameters with DFT. In addition, I will present the most interesting results of my calculations for magnetically hard materials obtained over the past few years.
I will start with the determination of structural parameters (lattice parameters, atomic positions, symmetry groups), formation energies and modeling of chemical disorder using the supercell method and the virtual crystal approximation. I will discuss the possibility of modeling tetragonal, hexagonal and orthorhombic systems. Using the example of cementite derivatives of (Fe-Co)3(B-C), I will present the possibility of modeling the full ranges of pseudo-binary systems. In addition, I will present example calculation results for L10 FePt, L10 FeNi, Fe3C, CeFe12, Fe-Co and Fe-Co-C phases.
I will show what effect the choice of exchange-correlation potential has on the MAE, and how the MAE is related to the magnetic moment, which can be determined by fully relativistic fixed spin moment calculations. The above method also makes it possible to translate changes in magnetic moment values into changes in temperature, and thus obtain the often unintuitive temperature dependence of MAE. I will also present the results of systematic calculations of the change in Curie temperature as a function of concentration and dopant element.
In summary, a number of structural and magnetic properties of magnetically hard materials are available through first-principles calculations. Recognizing the potential and limitations of DFT methods will allow for better collaboration between theoretical and experimental groups searching for new permanent magnets.
References:
[1] J. Snarski-Adamski, M. Werwiński, J. Rychły-Gruszecka, Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study, APL Materials. 13 (2025) 021117.
[2] W. Marciniak, M. Werwiński, Structural and magnetic properties of Fe-Co-C alloys with tetragonal deformation: A first-principles study, Phys. Rev. B. 108 (2023) 214433.
[3] J. Snarski-Adamski, M. Werwiński, Effect of transition metal doping on magnetic hardness of CeFe12-based compounds, J. Magn. Magn. Mater. 554 (2022) 169309.
[4] J. Snarski-Adamski, J. Rychły, M. Werwiński, Magnetic properties of 3d, 4d, and 5d transition-metal atomic monolayers in Fe/TM/Fe sandwiches: Systematic first-principles study, J. Magn. Magn. Mater. 546 (2022) 168828.
[5] M. Werwiński, W. Marciniak, Ab initio study of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L10 FeNi (tetrataenite), J. Phys. D: Applied Physics. 50 (2017) 495008.
[6] J. Marciniak, W. Marciniak, M. Werwiński, DFT calculation of intrinsic properties of magnetically hard phase L10 FePt, J. Magn. Magn. Mater. 556 (2022) 169347.
I will start with the determination of structural parameters (lattice parameters, atomic positions, symmetry groups), formation energies and modeling of chemical disorder using the supercell method and the virtual crystal approximation. I will discuss the possibility of modeling tetragonal, hexagonal and orthorhombic systems. Using the example of cementite derivatives of (Fe-Co)3(B-C), I will present the possibility of modeling the full ranges of pseudo-binary systems. In addition, I will present example calculation results for L10 FePt, L10 FeNi, Fe3C, CeFe12, Fe-Co and Fe-Co-C phases.
I will show what effect the choice of exchange-correlation potential has on the MAE, and how the MAE is related to the magnetic moment, which can be determined by fully relativistic fixed spin moment calculations. The above method also makes it possible to translate changes in magnetic moment values into changes in temperature, and thus obtain the often unintuitive temperature dependence of MAE. I will also present the results of systematic calculations of the change in Curie temperature as a function of concentration and dopant element.
In summary, a number of structural and magnetic properties of magnetically hard materials are available through first-principles calculations. Recognizing the potential and limitations of DFT methods will allow for better collaboration between theoretical and experimental groups searching for new permanent magnets.
References:
[1] J. Snarski-Adamski, M. Werwiński, J. Rychły-Gruszecka, Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study, APL Materials. 13 (2025) 021117.
[2] W. Marciniak, M. Werwiński, Structural and magnetic properties of Fe-Co-C alloys with tetragonal deformation: A first-principles study, Phys. Rev. B. 108 (2023) 214433.
[3] J. Snarski-Adamski, M. Werwiński, Effect of transition metal doping on magnetic hardness of CeFe12-based compounds, J. Magn. Magn. Mater. 554 (2022) 169309.
[4] J. Snarski-Adamski, J. Rychły, M. Werwiński, Magnetic properties of 3d, 4d, and 5d transition-metal atomic monolayers in Fe/TM/Fe sandwiches: Systematic first-principles study, J. Magn. Magn. Mater. 546 (2022) 168828.
[5] M. Werwiński, W. Marciniak, Ab initio study of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L10 FeNi (tetrataenite), J. Phys. D: Applied Physics. 50 (2017) 495008.
[6] J. Marciniak, W. Marciniak, M. Werwiński, DFT calculation of intrinsic properties of magnetically hard phase L10 FePt, J. Magn. Magn. Mater. 556 (2022) 169347.