| 1. |
- Pauwels, D., et al.
(författare)
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Gamow-Teller decay population of Ni-64 levels in the decay of 1(+) Co-64
- 2012
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 86:6, s. 064318-
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Tidskriftsartikel (refereegranskat)abstract
- The Co-64 beta-decay feeding levels in the well-studied Ni-64 nucleus were investigated. Whereas the previously known Co-64 decay scheme merely contained 2 gamma rays, the decay scheme established in this work contains 18, of which 5 are observed in this work and 6 were previously observed in an (n, gamma) study but not placed in the Ni-64 level scheme. Surprisingly, one additional level-placed at an excitation energy of 3578.7 keV-could be determined. The observed beta-decay paths involve allowed nu f(5/2) -> pi f(7/2) and nu p(1/2) -> pi p(3/2) transitions. Three strongly fed levels around 4 MeV are interpreted to possess possible proton-intruder character.
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| 2. |
- Radulov, D., et al.
(författare)
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beta decay of Mn-61 to levels in Fe-61
- 2013
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Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 88:1, s. 014307-
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Tidskriftsartikel (refereegranskat)abstract
- A detailed beta-decay study of Mn-61 is presented, yielding extended information on the level structure of Fe-61. Pure beams were obtained at ISOLDE, CERN, after selective laser ionization and mass separation of fission products from the bombardment of a UCx target by 1.4-GeV protons. The beta and gamma information was detected by two MiniBall clusters and three Delta E plastic scintillators. The new Mn-61 decay scheme reveals 48 gamma transitions, distributed over 20 excited states. A comparison to the decay scheme of Mn-59 and excited states in Fe-59 is made. Shell-model calculations with two different interactions are performed in order to compare the nuclear structure of the two neighboring odd-A iron isotopes. Tentative spin and parities of several excited states in Fe-61 are assigned on the basis of beta-decay feeding patterns in both Fe-59,Fe-61 and of results from the theoretical shell-model calculations.
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| 3. |
- Radulov, I. A., et al.
(författare)
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Production of net-shape Mn-Al permanent magnets by electron beam melting
- 2019
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Ingår i: Additive Manufacturing. - : Elsevier BV. - 2214-8604 .- 2214-7810. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- The main goal of this work is the adoption of additive manufacturing for the production of inexpensive rare-earth free MnAl-based permanent magnets. The use of more advanced binder-free additive manufacturing technique such as Electron Beam Melting (EBM) allows obtaining fully-dense magnetic materials with advanced topology and complex shapes. We focus on the feasibility of controlling the phase formation in additively manufactured Mn-Al alloys by employing post-manufacturing heat treatment. The as-manufactured EBM samples contain 8% of the desired ferromagnetic τ-MnAl phase. After the optimized annealing treatment, the content of the τ-phase was increased to 90%. This sample has a coercivity value of 0.15 T, which is also the maximum achieved in conventionally produced binary MnAl magnets. Moreover, the EBM samples are fully dense and have the same density as the samples produced by conventional melting density.
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| 4. |
- Edström, Alexander, et al.
(författare)
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Magnetic properties of (Fe1-xCox)(2)B alloys and the effect of doping by 5d elements
- 2015
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 92:17
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Tidskriftsartikel (refereegranskat)abstract
- We have explored, computationally and experimentally, the magnetic properties of (Fe1-xCox)(2)B alloys. Calculations provide a good agreement with experiment in terms of the saturation magnetization and the magnetocrystalline anisotropy energy with some difficulty in describing Co2B, for which it is found that both full potential effects and electron correlations treated within dynamical mean field theory are of importance for a correct description. The material exhibits a uniaxial magnetic anisotropy for a range of cobalt concentrations between x = 0.1 and x = 0.5. A simple model for the temperature dependence of magnetic anisotropy suggests that the complicated nonmonotonic behavior is mainly due to variations in the band structure as the exchange splitting is reduced by temperature. Using density functional theory based calculations we have explored the effect of substitutionally doping the transition metal sublattice by the whole range of 5d transition metals and found that doping by Re or W elements should significantly enhance the magnetocrystalline anisotropy energy. Experimentally, W doping did not succeed in enhancing the magnetic anisotropy due to formation of other phases. On the other hand, doping by Ir and Re was successful and resulted in magnetic anisotropies that are in agreement with theoretical predictions. In particular, doping by 2.5 at.% of Re on the Fe/Co site shows a magnetocrystalline anisotropy energy which is increased by 50% compared to its parent (Fe0.7Co0.3)(2)B compound, making this system interesting, for example, in the context of permanent magnet replacement materials or in other areas where a large magnetic anisotropy is of importance.
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| 5. |
- Kuz'min, M. D., et al.
(författare)
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Magnetic anisotropy of La2Co7
- 2015
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 118:5
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Tidskriftsartikel (refereegranskat)abstract
- A magnetization study of a La2Co7 single crystal has obtained the following anisotropy constants: K-1 = 1.4 MJ/m(3) and K-2 = 0.02 MJ/m(3) (at room temperature). The corresponding anisotropy field is 6.7 T; an earlier report of a much higher value (17 T) has not been confirmed. A significant (10%) magnetization anisotropy has been observed. Density-functional calculations are in qualitative agreement with the new data. (C) 2015 AIP Publishing LLC.
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| 6. |
- Viskadourakis, Z., et al.
(författare)
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Low-temperature ferroelectric phase and magnetoelectric coupling in underdoped La2CuO4+x
- 2012
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 85:21
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of ferroelectricity below 4.5 K in highly underdoped La2CuO4+x accompanied by slow charge dynamics which develop below T similar to 40 K. An anisotropic magnetoelectric response has also been observed, indicating considerable spin-charge coupling in this lightly doped parent high-temperature copper-oxide superconductor. The ferroelectric state is proposed to develop from polar nanoregions, in which spatial inversion symmetry is locally broken due to nonstoichiometric carrier doping.
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