Effects of strain and interface on magnetic anisotropy of FeCo/FePt: A first principles study
TL;DR: In this paper, the structural and magnetic properties of hybrid bilayer FeCo/FePt bilayer bilayers were explored using the full potential linearized augmented plane wave method, and the effect of interface hybridization and strain induced in FeCo by FePt buffer layer was studied.
About: This article is published in Computational Materials Science.The article was published on 2016-05-01. It has received 3 citations till now. The article focuses on the topics: Magnetocrystalline anisotropy & Magnetic anisotropy.
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TL;DR: In this article, the electronic structure and the magnetocrystalline anisotropy of impurity (Li, Be, B, C, and N) doped α-Fe16N2 were studied by using full potential linearized augmented plane wave method (FLAPW).
10 citations
TL;DR: In this article, the authors investigated the interface effect on the electronic structure and the magnetic properties of multilayer Fe16N2/Ag/Fe 16N2 and Fe16 n2/Au/Fe16N 2 and found substantial enhancements in the magnetocrystalline anisotropy constant and the coercive field due to interface effect.
Abstract: Using the first principles method, we investigated the interface effect on the electronic structure and the magnetic properties of multilayer Fe16N2/Ag/Fe16N2 and Fe16N2/Au/Fe16N2. The thicknesses of Ag (100) and Au (100) were fixed to three monolayers, and the lattice mismatch was about 1%. The magnetic moment of Fe atoms at the interface was suppressed due to hybridization with non-magnetic Ag and Au atoms. Due to this reduction in the magnetic moments and also because of the non-magnetic volume of the Ag and Au layer, an overall 40% suppression of the magnetization was found in both systems. The hybridization between interface Ag (Au) and Fe atoms and the spin-orbit coupling associated with Ag (Au) atoms mainly contributed to the enhancement of the magnetocrystalline anisotropy. The magnetocrystalline anisotropy constant was enhanced from 0.57 MJ/m3 in pure Fe16N2 to 1.58 MJ/m3 and 0.89 MJ/m3 in Fe16N2/Ag/Fe16N2 and Fe16N2/Au/Fe16N2 multilayer systems, respectively. This enhancement in magnetocrystalline anisotropy results in an enhancement of the coercive field. The coercive fields were about 30 and 16.7 kOe in the Ag and the Au multilayer systems, respectively. Overall, we found substantial enhancements in the magnetocrystalline anisotropy constant and the coercive field due to the interface effect. This finding may suggest that the Fe16N2/Ag/Fe16N2 and the Fe16N2/Au/Fe16N2 structures can be utilized for potential rare-earth-free permanent magnets.
1 citations
TL;DR: In this paper , Ru doping is used to enhance the magnetic properties of (Fe3Co7)1−xRux nanoparticles with different Ru doping contents using a polyvinylpyrrolidone (PVP)-assisted liquid phase reduction process.
1 citations
References
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TL;DR: A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.
Abstract: Generalized gradient approximations (GGA’s) for the exchange-correlation energy improve upon the local spin density (LSD) description of atoms, molecules, and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental constants. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential. [S0031-9007(96)01479-2] PACS numbers: 71.15.Mb, 71.45.Gm Kohn-Sham density functional theory [1,2] is widely used for self-consistent-field electronic structure calculations of the ground-state properties of atoms, molecules, and solids. In this theory, only the exchange-correlation energy EXC › EX 1 EC as a functional of the electron spin densities n"srd and n#srd must be approximated. The most popular functionals have a form appropriate for slowly varying densities: the local spin density (LSD) approximation Z d 3 rn e unif
146,533 citations
TL;DR: An efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set is presented and the application of Pulay's DIIS method to the iterative diagonalization of large matrices will be discussed.
Abstract: We present an efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrices will be discussed. Our approach is stable, reliable, and minimizes the number of order ${\mathit{N}}_{\mathrm{atoms}}^{3}$ operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special ``metric'' and a special ``preconditioning'' optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calculations. It will be shown that the number of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order ${\mathit{N}}_{\mathrm{atoms}}^{2}$ scaling is found for systems containing up to 1000 electrons. If we take into account that the number of k points can be decreased linearly with the system size, the overall scaling can approach ${\mathit{N}}_{\mathrm{atoms}}$. We have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large number of different systems (liquid and amorphous semiconductors, liquid simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable. \textcopyright{} 1996 The American Physical Society.
81,985 citations
TL;DR: In this paper, the authors present an ab initio quantum-mechanical molecular-dynamics calculations based on the calculation of the electronic ground state and of the Hellmann-Feynman forces in the local density approximation.
Abstract: We present ab initio quantum-mechanical molecular-dynamics calculations based on the calculation of the electronic ground state and of the Hellmann-Feynman forces in the local-density approximation at each molecular-dynamics step. This is possible using conjugate-gradient techniques for energy minimization, and predicting the wave functions for new ionic positions using subspace alignment. This approach avoids the instabilities inherent in quantum-mechanical molecular-dynamics calculations for metals based on the use of a fictitious Newtonian dynamics for the electronic degrees of freedom. This method gives perfect control of the adiabaticity and allows us to perform simulations over several picoseconds.
32,798 citations
TL;DR: In this paper, a new compound composed of Nd, Fe, and a small quantity of B (about 1 wt. %) has been found, which has a tetragonal structure with lattice constants a=0.880 nm and c=1.221 nm.
Abstract: A new compound composed of Nd, Fe, and a small quantity of B (about 1 wt. %) has been found, which has a tetragonal structure with lattice constants a=0.880 nm and c=1.221 nm. This phase, which has the approximate composition, 12 at. % Nd, 6 at. % B and balance Fe, possesses remarkable magnetic properties. From the approach to saturation an anisotroy constant of about 3.5 MJ/m3 can be calculated, while saturation magnetization amounts to 1.35 T. The magnetization versus temperature curve shows a Curie temperature of 585 K, which is much higher than those of the Fe and light rare earth binary compounds. Based on the new compound, sintered permanent magnets have been developed which have a record high energy product. Permanent magnet properties and physical properties of a typical specimen which has the composition Nd15B8Fe77 are as follows: Br =1.23 T, HcB =880 kA/m, HcI =960 kA/m, (BH)max =290 kJ/m3, temperature coefficient of Br =−1260 ppm/K, density=7.4 Mg/m3, specific resistivity=1.4 μΩm, Vickers hardn...
2,525 citations
TL;DR: In this paper, the spin-orbit interaction is included as a perturbation once the'relativistic' spin-polarised bands and wavefunctions have been obtained.
Abstract: A technique for reduction of the Dirac equation, which initially omits the spin-orbit interaction (thus keeping spin as a good quantum number), but retains all other relativistic kinematic effects such as mass-velocity, Darwin, and higher order terms is presented. The spin-orbit interaction can be included as a perturbation once the 'relativistic' spin-polarised bands and wavefunctions have been obtained. The technique is used together with the local spin density approximation for exchange and correlation to calculate the self-consistent charge and spin density of a neutral Gd atom. The calculated magnetic form factor agrees extremely well with experiment. Comparison with a paramagnetic RAPW calculation shows the procedure should be accurate and fast for general band structure determinations.
1,724 citations