d.j.gonsiorkiewicz* 1, j.c.krause 1, a. v. dos santos 1 and c. paduani 2 1 uri – santo Ângelo- rs...
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D.J.Gonsiorkiewicz*1, J.C.Krause1, A. V. dos Santos1 and C. Paduani2
1URI – Santo Ângelo- RS - Brazil2UFSC – Florianópolis – SC - Brazil
Investigation of the magnetic properties of substituted iron nitrides Fe3MN, M=Li, Be, Sm e
Gd.
Investigation of the magnetic properties of substituted iron nitrides Fe3MN, M=Li, Be, Sm e
Gd.
Bibliografia:
[1] E. L. Peltzer y Blancá, J. Desimoni,, N. E. Christensen, H. Emmerich, S. Cottenier, The magnetization of γ′-
Fe4N: theory vs. experiment. Physica Status Solidi B 246, No. 5, 909–928, 2009.
[2] C. Paduani, Electronic structure of the perovskite-type nitride RuFe3N, Journal of Magnetism and Magnetic
Materials. 278, 231–236, 2004.
[3] A.N. Timshevskii, V.A. Timoshevxkii, B.Z. Yanchitsky, V.A. Yavna, Electronic structure, hyperfine
interactions and disordering affects in iron nitride Fe4N. Computacional Materials Science, 22, 99-105, 2001.
[4] P. Blaha, K.Schwarz, G. Madsen, D. Kvasnicka, J. Luitz. WIEN2k - An Augmented Plane Wave Plus Local
Orbitals Program for Calculating Crystal Properties - User’s Guide. October, 2009.
Bibliografia:
[1] E. L. Peltzer y Blancá, J. Desimoni,, N. E. Christensen, H. Emmerich, S. Cottenier, The magnetization of γ′-
Fe4N: theory vs. experiment. Physica Status Solidi B 246, No. 5, 909–928, 2009.
[2] C. Paduani, Electronic structure of the perovskite-type nitride RuFe3N, Journal of Magnetism and Magnetic
Materials. 278, 231–236, 2004.
[3] A.N. Timshevskii, V.A. Timoshevxkii, B.Z. Yanchitsky, V.A. Yavna, Electronic structure, hyperfine
interactions and disordering affects in iron nitride Fe4N. Computacional Materials Science, 22, 99-105, 2001.
[4] P. Blaha, K.Schwarz, G. Madsen, D. Kvasnicka, J. Luitz. WIEN2k - An Augmented Plane Wave Plus Local
Orbitals Program for Calculating Crystal Properties - User’s Guide. October, 2009.
Abstract
The linearized augmented plane wave (LAPW) method as implemented in the WIEN2K
code is used to investigate the electronic structure of the ferromagnetic compound '-Fe4N
(fcc) with the substitution of Be, Li, Sm and Gd for Fe at FeI (corner) sites. The total energy is
calculated in several cell volumes for each compound to determine their stability. From the
calculations are obtained the magnetic moments, density of states (DOS) and electronic
density at the equilibrium volume. Electronic structure calculations were performed for the
Fe4N compound, for which it was obtained a lattice parameter of 3.8072 Å (consistent with the
literature), as well as for the compounds BeFe3N, LiFe3N, SmFe3N and GdFe3N. From
calculations of the densities of states we observed for both these compounds a strong
interaction between Fe atoms with N atoms, whereas the interaction of N atoms with the
impurity atoms (Be and Li) is very weak. In the compounds SmFe3N and GdFe3N similar
interactions were also observed through hybridizations with the p orbitals of the substituents.
The results indicate that both compounds can be formed in stable fcc structure.
Objectives
Investigate through DFT calculations the stability, magnetic properties, electronic
densities and density of states in '-type nitrides (Fe4-XMXN, where M = Be, Li, Sm and Gd).
Methodology
First the equilibrium lattice parameter was calculated for the '-Fe4N compound . With
the same unit cell of '-Fe4N calculations were performed for the properties of the BeFe3N,
LiFe3N, SmFe3N and GdFe3N compounds . The space group used is P (cubic cell), and beryllium,
lithium, samarium or gadolinium were inserted at the corner sites in the perovskite structure.
Table 1: Data entered into the WIEN2K to calculate the electronic properties of Fe4N.
Results
The equilibrium lattice parameters obtained are: 3.8033 Å for Fe4N, 3.6981 Å for BeFe3N,
3.7872 Å for LiFe3N, 4,23 Å for SmFe3N and 4,02Å for GdFe3N. Electronic densities of states
demonstrate for both compounds, BeFe3N and LiFe3N, strong interactions between the d
orbitals of the Fe atoms with the s orbitals of the N atoms, and the interaction of the
impurities is very weak. For the and SmFe3N GdFe3N compounds were observed hybridization
between the orbitals of iron and nitrogen with the substituents (Sm or Gd). For the magnetic
moment we obtained the following results: 10.41 µB for Fe4N , 4.68 µB for BeFe3N, 7.30 µB for
LiFe3N, -1.06551µB for SmFe3N and 7.44148µB GdFe3N.
Conclusion
The results show that the lattice parameter, for the compounds containing Li and Be,
decreases with the insertion of impurity atoms, and it increases with the substitution of Sm e
Gd. From the density of States we see strong interactions between the iron atoms and
nitrogen atoms, whereas the interactions with lithium or beryllium are very weak. With Sm
and Gd we observed strong interactions with nitrogen. The magnetic moments decrease of
this with the insertion of substituents, and an antiferromagnetic behavior was identified for
the samarium compound. The calculations for the total energy show that these compounds
can be experimentally, obtained but their stabilities are smaller than for -Fe4N.
(a) (b) (c)
(a) (b) (c)
Figure 4: Density of states for the LiFe3N : (a) s, p and d states for Fe; (b) s and p states for N; (c) s and p states for Li.
*PROBIC-FAPERGS
Compound Lattice Parameter (Å)
Space group Atomic positions Atomic radius(a.u)
Fe4N 3.797 [1] Pm-3m (221)
FeI (0.0,0.0,0.0)
FeII x(0.5,0.5,0.0) y(0.5,0.0,0.5) z(0.0,0.5,0.5)N (0.5,0.5,0.5)
Fe I: 2.0FeII: 2.0
N: 1.38
Figure 5: Density of states for the SmFe3N : (a) s, p and d states for the Fe; (b) s and p states for N;
(c) s states for Sm; (d) p states for Sm.
(a) (b) (c) (d)
(a) (b) (c) (d)
Figure 6: Density of states for the GdFe3N : (a) s, p and d states for the Fe; (b) s and p states for N;
(c) s states for Gd; (d) p states for Gd.
Figure 1: Unit cell of perovskite structure.
Figure 3: Density of states for the BeFe3N : (a) s, p and d states for Fe; (b) s and p states for N and (c) s and p states of Be.
Figure 2: Total Energy curves for compounds.