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| 2. |
- Katcko, K., et al.
(författare)
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Spin-driven electrical power generation at room temperature
- 2019
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Ingår i: Communications Physics. - : NATURE PUBLISHING GROUP. - 2399-3650. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- On-going research is exploring novel energy concepts ranging from classical to quantum thermodynamics. Ferromagnets carry substantial built-in energy due to ordered electron spins. Here, we propose to generate electrical power at room temperature by utilizing this magnetic energy to harvest thermal fluctuations on paramagnetic centers using spintronics. Our spin engine rectifies current fluctuations across the paramagnetic centers' spin states by utilizing so-called 'spinterfaces' with high spin polarization. Analytical and ab-initio theories suggest that experimental data at room temperature from a single MgO magnetic tunnel junction (MTJ) be linked to this spin engine. Device downscaling, other spintronic solutions to select a transport spin channel, and dual oxide/organic materials tracks to introduce paramagnetic centers into the tunnel barrier, widen opportunities for routine device reproduction. At present MgO MTJ densities in next-generation memories, this spin engine could lead to 'always-on' areal power densities that are highly competitive relative to other energy harvesting strategies.
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| 3. |
- Galanakis, I, et al.
(författare)
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Sign reversal of the orbital moment via ligand states - art. no. 172405
- 2001
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Ingår i: PHYSICAL REVIEW B. - : AMERICAN PHYSICAL SOC. - 0163-1829. ; 6317:17, s. 2405-
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that the coupling between spin and orbital moments in magnetic systems may-for certain materials-be reversed from antiparallel to parallel, via the influence of ligand states. This is exemplified by first-principles calculations for an
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| 4. |
- Galanakis, I, et al.
(författare)
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Tuning the orbital moment in transition metal compounds using ligand states
- 2001
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Ingår i: JOURNAL OF PHYSICS-CONDENSED MATTER. - : IOP PUBLISHING LTD. - 0953-8984. ; 13:20, s. 4553-4566
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Tidskriftsartikel (refereegranskat)abstract
- The influence of ligand states on the orbital magnetism of a 3d atom in a ferromagnetic compound has been studied using an ab initio technique. It is shown, using VAu4, MnAu4 and VPt3 as examples, that the large spin-orbit coupling of the 5d atom is respo
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| 5. |
- Wills, J. M., et al.
(författare)
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Total Energy and Forces : Some Numerical Examples
- 2010
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Ingår i: Full-Potential Electronic Structure Method. - Berlin, Heidelberg : Springer Nature. ; , s. 101-109
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Bokkapitel (refereegranskat)abstract
- Numerical examples of calculations of total energy, equation of state and Hellman-Feynman forces are given. The calculation of first principles phonons is also exemplified with fcc Al and bcc U. A comparison between a few selected exchange and correlation functionals is also made for the calculation of the equation of state.
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| 6. |
- Ahuja, R, et al.
(författare)
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Optical properties of graphite from first-principles calculations
- 1997
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Ingår i: PHYSICAL REVIEW B-CONDENSED MATTER. - : AMER INST PHYSICS. - 0163-1829. ; 55:8, s. 4999-5005
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present theoretical results for the frequency-dependent dielectric response, both for the electric field parallel and perpendicular to the c axis of graphite. The calculations are performed using a full-potential linear muffin-tin orbital method. Our c
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| 7. |
- Araujo, Carlos Moyses, et al.
(författare)
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Electronic and optical properties of MgH2: a first-principle GW investigation
- 2005
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 98:9, s. 096106-
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of MgH2 is studied using the state of the art all-electron projector-augmented-wave GW approximation. Both the ground-state and the high-pressure transformations are considered in this investigation. We have found an indirect (direct) band-gap of 5.58 eV (6.52 eV) for α-MgH2, which has a good agreement with the experimental findings. For the γ- and β-phases, we have found indirect (direct) band-gap values of 5.24 eV (5.33 eV) and 3.90 eV (4.72 eV), respectively. The optical properties are investigated by means of the complex dielectric function, which is calculated within the framework of a full-potential linearized augmented plane wave method and corrected by scissor operators. All phases are found to be color neutral insulators.
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| 8. |
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| 9. |
- Iusan, Diana, et al.
(författare)
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Effect of diffusion and alloying on the magnetic and transport properties of Fe/V/Fe trilayers
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:2, s. 024412-
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic and transport properties of the Fe/V/Fe(001) trilayers were studied using the self-consistent Green's function technique based on the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation. The coherent potential approximation was used to describe the effects of interdiffusion and alloying at the interfaces on the properties of the semi-infinite bcc Fe(001)/mFe/nV/mFe/Fe(001) trilayers. The electric conductance was calculated using the Kubo-Landauer formalism, in the current-perpendicular-to-plane geometry. It is shown that a dipole moment is created at the Fe/V interface due to the charge transfer from vanadium to iron, and a small induced magnetic moment is present in the first vanadium layer and is antiparallel to that of iron. The interlayer exchange coupling shows rapid oscillations for small spacer thicknesses, and the interdiffusion and alloying at the interface stabilize the ferromagnetic coupling. Moreover, the interdiffusion reduces the vanadium-induced magnetic moment and increases the iron magnetic moment at the interface. The giant magnetoresistance (GMR) ratio presents damped oscillations as a function of the vanadium spacer thickness. The interdiffusion and the presence of Mn impurities at the interface reduce considerably the GMR ratio and produce results that are in agreement with experimental data.
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| 10. |
- Kanchana, V., et al.
(författare)
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Electronic structure and x-ray magnetic circular dichroism of Sr2FeMoO6 : Ab initio calculations
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:22
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical investigations of the electronic structure, x-ray absorption, and x-ray magnetic circular dichroism (XMCD) at the Fe L-2,L-3 and Mo L-2,L-3 edges of Sr2FeMoO6 are carried out by means of the generalized gradient approximation. The magnetic coupling between Fe and Mo is found to be antiparallel, which gives direct confirmation of ferrimagnetic ordering and settles controversies existing between the earlier experimental reports. This is also confirmed by our good agreement of the Mo L-2,L-3 edges with experiment. Using our theoretical spectra, we recalculate the spin and orbital magnetic moments by means of the XMCD sum rules and compare the results with a direct self-consistent calculation and experiment.
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