| 1. |
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| 2. |
- ASPELMEIER, A, et al.
(författare)
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AC SUSCEPTIBILITY MEASUREMENTS OF MAGNETIC MONOLAYERS - MCXD, MOKE, AND MUTUAL INDUCTANCE
- 1995
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Ingår i: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS. - : ELSEVIER SCIENCE BV. - 0304-8853. ; 146:3, s. 256-266
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Tidskriftsartikel (refereegranskat)abstract
- A refined analysis of dispersive and absorptive contributions to the complex magnetic susceptibility yields detailed information on magnetic and structural properties of ultrathin films. The new ac modulated magnetic circular X-ray dichroism (MCXD) techni
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| 3. |
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| 4. |
- Dey, J., et al.
(författare)
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Helical magnetic structure of epitaxial films of nanolaminated Mn2GaC MAX phase
- 2023
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 108:5
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Tidskriftsartikel (refereegranskat)abstract
- Nanolaminated Mn2GaC epitaxial films crystallizing in the hexagonal structure belong to the family of MAX phase compounds and display complex magnetic interactions. While the critical temperature of the order-disorder transition is 507 K, at around 214 K this compound undergoes a first-order phase transition with the magnetic structure below the transition point not being fully resolved. Previous studies indicated a noncollinear spin arrangement, but a specific magnetic structure could not be defined. In this work we present the results of 69Ga, 71Ga, and 55Mn NMR experiments performed at 4.2 K in an external in-plane magnetic field up to 1 T. The in-depth analysis of the experimental results shows a helical magnetic structure consisting of the ferromagnetically coupled Mn-C-Mn slabs that are twisted across the Ga layer by 167.2 degrees with respect to the next Mn-C-Mn slab. As a result, the magnetic structure presents a spiral propagating along the out-of-plane direction (hexagonal c axis) with a pitch of around 14 lattice constants.
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| 5. |
- Dey, J., et al.
(författare)
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Non-collinear magnetic structure of the MAX phase Mn2GaC epitaxial films inferred from zero-field NMR study (CE-5:L05)
- 2023
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Ingår i: Ceramics International. - : ELSEVIER SCI LTD. - 0272-8842 .- 1873-3956. ; 49:14, s. 24235-24238
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Tidskriftsartikel (refereegranskat)abstract
- Zero-field NMR investigations on the 69Ga, 71Ga, and 55Mn nuclei have been performed at 4.2 K on a 100 nm thick epitaxial Mn2GaC(0001) MAX phase film grown on a MgO(111) substrate. This nano-laminated structure consists of ferromagnetic Mn-C-Mn stacks interleaved with monolayers of gallium. A resolved quadrupolar structure of the observed gallium resonances is a fingerprint of a well-defined crystal field confirming high crystal quality. The nuclei of non-magnetic gallium atoms are shown to experience the transferred hyperfine magnetic field of 15.75 T (& PLUSMN;0.05 T), which is due to polarization of their 4s electron shell by the magnetic moments of manganese neighbors, evidencing the presence of an uncompensated ferromagnetic moment within the manganese sublattice. The average magnetic moment of manganese was found to be around 2 & mu;B, strongly contrasting with the reported remnant magnetization of only 0.3 & mu;B. Moreover, the 55Mn NMR spectrum in-dicates the presence of magnetically non-equivalent manganese sites within this structure. The observed features of the 69,71Ga and 55Mn NMR spectra cannot be reconciled with any of the hitherto proposed collinear ar-rangements of manganese moments and suggest their non-collinear arrangement across a gallium layer. Nevertheless a more advanced study is required to elucidate the detailed nature of magnetic structure in this material.
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| 6. |
- Durr, Hermann A., et al.
(författare)
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A Closer Look Into Magnetism : Opportunities With Synchrotron Radiation
- 2009
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Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 45:1, s. 15-57
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Forskningsöversikt (refereegranskat)abstract
- The unique properties of synchrotron radiation, such as broad energy spectrum, variable light polarization, and flexible time structure, have made it an enormously powerful tool in the study of magnetic phenomena and materials. The refinement of experimental techniques has led to many new research opportunities, keeping up with the challenges put up by modern magnetism research. In this contribution, we review some of the recent developments in the application of synchrotron radiation and particularly soft X-rays to current problems in magnetism, and we discuss future perspectives.
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| 7. |
- Fu, Yu, et al.
(författare)
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Tailored magnetic anisotropy in an amorphous trilayer
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:11, s. 113908-
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Tidskriftsartikel (refereegranskat)abstract
- An amorphous Co68Fe24Zr8(3 nm)/Al70Zr30(3 nm)/Co68Fe24Zr8(3 nm) trilayer system has been investigated using in-plane and out-of-plane angular dependent ferromagnetic resonance at different frequencies. The in-plane magnetic anisotropy is uniaxial, retaining its value of (2.9 +/- 0.1) x 10(3) J/m(3) for each magnetic layer, whereas its direction was tailored independently in an arbitrary manner by applying an external magnetic field during the film deposition. The perpendicular anisotropy constant, supposed to reflect the interface quality, is nearly identical for both layers. Furthermore, the magnetic layers act independently upon each other due to the absence of interlayer coupling.
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| 8. |
- Kronast, F., et al.
(författare)
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Element-specific magnetic hysteresis of individual 18 nm Fe nanocubes
- 2011
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 11:4, s. 1710-1715
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Tidskriftsartikel (refereegranskat)abstract
- Correlating the electronic structure and magnetic response with the morphology and crystal structure of the same single ferromagnetic nanoparticle has been up to now an unresolved challenge. Here, we present measurements of the element-specific electronic structure and magnetic response as a function of magnetic field amplitude and orientation for chemically synthesized single Fe nanocubes with 18 nm edge length. Magnetic states and interactions of monomers, dimers, and trimers are analyzed by X-ray photoemission electron microscopy for different particle arrangements. The element-specific electronic structure can be probed and correlated with the changes of magnetic properties. This approach opens new possibilities for a deeper understanding of the collective response of magnetic nanohybrids in multifunctional materials and in nanomagnetic colloidal suspensions used in biomedical and engineering technologies. © 2011 American Chemical Society.
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| 9. |
- Anisimov, AN, et al.
(författare)
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Magnetic anisotropies of Fe-n/V-m(001) superlattices determined by Ferromagnetic Resonance
- 1998
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Ingår i: IEEE TRANSACTIONS ON MAGNETICS. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9464. ; 34:4, s. 873-875
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The temperature-dependent magnetic anisotropies of Fe-n/V-m(001) superlattices on MgO(001) were determined by Ferromagnetic Resonance (FMR). The re-layer thickness n ranges between 2 and 4 atomic layers. The shape anisotropy dominates, and the easy-axis o
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| 10. |
- Anisimov, AN, et al.
(författare)
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Orbital magnetism and magnetic anisotropy probed with ferromagnetic resonance
- 1999
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMERICAN PHYSICAL SOC. - 0031-9007. ; 82:11, s. 2390-2393
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Via ferromagnetic resonance both the magnetic anisotropy energy (MAE) and the spectroscopic splitting tensor (g tensor) for a bcc Fe-2/V-5(001) superlattice are measured independently. The theoretically proposed proportionality between the anisotropy of t
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| 11. |
- Anisimov, AN, et al.
(författare)
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The temperature-dependent in- and out-of-plane magnetic anisotropies in Fe-n/V-m(001) superlattices
- 1997
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Ingår i: JOURNAL OF PHYSICS-CONDENSED MATTER. - : IOP PUBLISHING LTD. - 0953-8984. ; 9:48, s. 10581-10593
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Fe-n/V-m(001) superlattices grown on MgO(001) are studied by ferromagnetic resonance (FMR). The temperature dependence of the second- and fourth-order in- and out-of-plane magnetic anisotropies were determined from azimuthal and polar angular-dependent FM
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| 12. |
- Flatten, Tim, et al.
(författare)
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Direct measurement of anisotropic conductivity in a nanolaminated (Mn0.5Cr0.5)(2)GaC thin film
- 2019
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Ingår i: Applied Physics Letters. - : AMER INST PHYSICS. - 0003-6951 .- 1077-3118. ; 115:9
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Tidskriftsartikel (refereegranskat)abstract
- The direct and parameter-free measurement of anisotropic electrical resistivity of a magnetic M(n+1)AX(n) (MAX) phase film is presented. A multitip scanning tunneling microscope is used to carry out 4-probe transport measurements with variable probe spacing s. The observation of the crossover from the 3D regime for small s to the 2D regime for large s enables the determination of both in-plane and perpendicular-to-plane resistivities rho(ab) and rho(c). A (Cr0.5Mn0.5)(2)GaC MAX phase film shows a large anisotropy ratio rho(c)/rho(ab) = 525 +/- 49. This is a consequence of the complex bonding scheme of MAX phases with covalent M-X and metallic M-M bonds in the MX planes and predominately covalent, but weaker bonds between the MX and A planes. Published under license by AIP Publishing.
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| 13. |
- Fu, Yu, et al.
(författare)
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Mechanism of tailored magnetic anisotropy in amorphous Co68Fe24Zr8 thin films
- 2014
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 104:7, s. 072409-
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of tailored magnetic anisotropy in amorphous Co68Fe24Zr8 thin films was investigated by ferromagnetic resonance (FMR) on samples deposited without an applied magnetic field, with an out-of-plane field and an in-plane field. Analysis of FMR spectra profiles, high frequency susceptibility calculations, and statistical simulations using a distribution of local uniaxial magnetic anisotropy reveal the presence of atomic configurations with local uniaxial anisotropy, of which the direction can be tailored while the magnitude remains at an intrinsically constant value of 3.0(2) kJ/m(3). The in-plane growth field remarkably sharpens the anisotropy distribution and increases the sample homogeneity. The results benefit designing multilayer spintronic devices based on highly homogeneous amorphous layers with tailored magnetic anisotropy.
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| 14. |
- Fu, Yu, et al.
(författare)
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Uniaxial anisotropy and its manipulation in amorphous Co68Fe24Zr8 thin films (invited)
- 2014
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 115:17, s. 172605-
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Tidskriftsartikel (refereegranskat)abstract
- We have proven that the growth of Co68Fe24Zr8 layers under external field yields a uniaxial anisotropy, defined by the direction of the field. No magnetic coupling is present between Co68Fe24Zr8 layers when separated by a 3 nm of Al70Zr30. The anisotropy axis can therefore be manipulated at will and the direction can be tailored, layer by layer in multilayers, by the choice of the direction of the applied field during growth. The g-factor (2.13) and the anisotropy constant, obtained from ferromagnetic resonance, support the existence of short-range order. The relation between the temperature dependences of magnetic anisotropy and magnetization are partially captured by Callen-Callen power law. (C) 2014 AIP Publishing LLC.
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| 15. |
- Mondal, Ritwik, et al.
(författare)
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Inertial effects in ultrafast spin dynamics
- 2023
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 579
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Forskningsöversikt (refereegranskat)abstract
- The dynamics of magnetic moments consists of a precession around the magnetic field direction and a relaxation towards the field to minimize the energy. While the magnetic moment and the angular momentum are conventionally assumed to be parallel to each other, at ultrafast time scales their directions become separated due to inertial effects. The inertial dynamics gives rise to additional high-frequency modes in the excitation spectrum of magnetic materials. Here, we review the recent theoretical and experimental advances in this emerging topic and discuss the open challenges and opportunities in the detection and the potential applications of inertial spin dynamics.
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| 16. |
- Poulopoulos, P, et al.
(författare)
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Magnetic anisotropy and exchange coupling in FenVm(001) superlattices on MgO(001)
- 1997
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Ingår i: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS. - : ELSEVIER SCIENCE BV. - 0304-8853. ; 170:1-2, s. 57-66
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Fe(0 0 1) single layers and FenVm(0 0 1) superlattices were epitaxially grown on MgO(0 0 1) substrates, where n and m denote the number of monolayers (ML) of the constituents within each modulation period. n and tn were varied between 3 and 14 ML. Structu
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| 17. |
- Salikhov, R., et al.
(författare)
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Enhanced spin-orbit coupling in tetragonally strained Fe-Co-B films
- 2017
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Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 29:27
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Tidskriftsartikel (refereegranskat)abstract
- Tetragonally strained interstitial Fe-Co-B alloys were synthesized as epitaxial films grown on a 20 nm thick Au0.55Cu0.45 buffer layer. Different ratios of the perpendicular to in-plane lattice constant c/a = 1.013, 1.034 and 1.02 were stabilized by adding interstitial boron with different concentrations 0, 4, and 10 at.%, respectively. Using ferromagnetic resonance (FMR) and x-ray magnetic circular dichroism (XMCD) we found that the total orbital magnetic moment significantly increases with increasing c/a ratio, indicating that reduced crystal symmetry and interstitial B leads to a noticeable enhancement of the effect of spin-orbit coupling (SOC) in the Fe-Co-B alloys. First-principles calculations reveal that the increase in orbital magnetic moment mainly originates from B impurities in octahedral position and the reduced symmetry around B atoms. These findings offer the possibility to enhance SOC phenomena - namely the magnetocrystalline anisotropy and the orbital moment - by stabilizing anisotropic strain by doping 4 at.% B. Results on the influence of B doping on the Fe-Co film microstructure, their coercive field and magnetic relaxation are also presented.
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| 18. |
- Salikhov, R., et al.
(författare)
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Magnetic properties of nanolaminated (Mo0.5Mn0.5)(2)GaC MAX phase
- 2017
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 121:16
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic properties of hexagonal (Mo0.5Mn0.5)(2)GaC MAX phase synthesized as epitaxial films on MgO (111) substrates with the c-axis perpendicular to the film plane are presented. The analysis of temperature-dependent ferromagnetic resonance (FMR) and magnetometry data reveals a ferro-to paramagnetic phase transition at 220 K. The electrical transport measurements at 5K show a negative magnetoresistance of 6% in a magnetic field of 9 T. Further analysis confirms the spin-dependent scattering of charge carriers in this layered material. A small perpendicular (c-axis) magnetocrystalline anisotropy energy density (MAE) of 4.5 kJ/m(3) at 100K was found using FMR. Accordingly, (Mo0.5Mn0.5)(2)GaC behaves similar to the (Cr0.5Mn0.5)(2)GaC MAX phase as a soft magnetic material. The density functional theory calculations reveal that the sign and the amplitude of the MAE can be very sensitive to (Mo0.5Mn0.5)(2)GaC lattice parameters, which may explain the measured soft magnetic properties. Published by AIP Publishing.
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| 19. |
- Tao, Quanzheng, et al.
(författare)
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Thin film synthesis and characterization of a chemically ordered magnetic nanolaminate (V,Mn)(3)GaC2
- 2016
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Ingår i: APL Materials. - : AMER INST PHYSICS. - 2166-532X. ; 4:8
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Tidskriftsartikel (refereegranskat)abstract
- We report on synthesis and characterization of a new magnetic nanolaminate (V,Mn)(3)GaC2, which is the first magnetic MAX phase of a 312 stoichiometry. Atomically resolved energy dispersive X-ray mapping of epitaxial thin films reveals a tendency of alternate chemical ordering between V and Mn, with atomic layers composed of primarily one element only. Magnetometry measurements reveal a ferromagnetic response between 50 K and 300 K, with indication of a magnetic ordering temperature well above room temperature. (C) 2016 Author(s).
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