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Eriksson, Olle
Publications (10 of 12) Show all publications
Koumpouras, K., Yudin, D., Adelmann, C., Bergman, A., Eriksson, O. & Pereiro, M. (2018). A majority gate with chiral magnetic solitons. Journal of Physics: Condensed Matter, 30(37), Article ID 375801.
Open this publication in new window or tab >>A majority gate with chiral magnetic solitons
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2018 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 30, no 37, article id 375801Article in journal (Refereed) Published
Abstract [en]

In magnetic materials, nontrivial spin textures may emerge due to the competition among different types of magnetic interactions. Among such spin textures, chiral magnetic solitons represent topologically protected spin configurations with particle-like properties. Based on atomistic spin dynamics simulations, we demonstrate that these chiral magnetic solitons are ideal to use for logical operations, and we demonstrate the functionality of a three- input majority gate, in which the input states can be controlled by applying an external electromagnetic field or spin-polarized currents. One of the main advantages of the proposed device is that the input and output signals are encoded in the chirality of solitons, that may be moved, allowing to perform logical operations using only minute electric currents. As an example we illustrate how the three input majority gate can be used to perform logical relations, such as Boolean AND and OR.

Place, publisher, year, edition, pages
IOP Publishing, 2018
Keywords
magnonics, majority gate, solitons, spin dynamics, magnetic nanodevices
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:oru:diva-68752 (URN)10.1088/1361-648X/aad82f (DOI)000442630600001 ()30079893 (PubMedID)
Funder
Swedish Research Council
Note

Funding Agencies:

KAW foundation  2013.0020  2012.0031 

eSSENCE  

CEA Enhanced Eurotalents program  

Russian Science Foundation  17-12-01359 

imecs Industrial Affiliation Program on Beyond CMOS devices  

Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2018-09-10Bibliographically approved
Shaw, J. M., Delczeg-Czirjak, E. K., Edwards, E. R. J., Kvashnin, Y., Thonig, D., Schoen, M. A. W., . . . Nembach, H. T. (2018). Magnetic damping in sputter-deposited Co2MnGe Heusler compounds with A2, B2, and L2(1) orders: Experiment and theory. Physical Review B, 97(9), Article ID 094420.
Open this publication in new window or tab >>Magnetic damping in sputter-deposited Co2MnGe Heusler compounds with A2, B2, and L2(1) orders: Experiment and theory
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2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, no 9, article id 094420Article in journal (Refereed) Published
Abstract [en]

We show that very low values of the magnetic damping parameter can be achieved in sputter deposited polycrystalline films of Co2MnGe annealed at relatively low temperatures ranging from 240 degrees C to 400 degrees C. Damping values as low as 0.0014 are obtained with an intrinsic value of 0.0010 after spin-pumping contributions are considered. Of importance to most applications is the low value of inhomogeneous linewidth that yields measured linewidths of 1.8 and 5.1 mT at 10 and 40 GHz, respectively. The damping parameter monotonically decreases as the B2 order of the films increases. This trend is reproduced and explained by ab initio calculations of the electronic structure and damping parameter. Here, the damping parameter is calculated as the structure evolves from A2 to B2 to L2(1) orders. The largest decrease in the damping parameter occurs during the A2 to B2 transition as the half-metallic phase becomes established.

Place, publisher, year, edition, pages
American Physical Society, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:oru:diva-66385 (URN)10.1103/PhysRevB.97.094420 (DOI)000427798500002 ()2-s2.0-85044408058 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2012.0031 2013.0030Swedish Research Council, 2016-04524 2016-06955 2013-08316
Note

Funding Agencies:

STandUP  

eSSENCE  

IARPA Cryogenic Computing Complexity program 

Available from: 2018-04-09 Created: 2018-04-09 Last updated: 2018-08-20Bibliographically approved
Keshavarz, S., Kontos, S., Wardecki, D., Kvashnin, Y. O., Pereiro, M., Panda, S. K., . . . Svedlindh, P. (2018). Magnetic properties of Ruddlesden-Popper phases Sr3−x Yx (Fe1.25 Ni0.75) O7−δ: A combined experimental and theoretical investigation. Physical Review Materials, 2(4), Article ID 044005.
Open this publication in new window or tab >>Magnetic properties of Ruddlesden-Popper phases Sr3−x Yx (Fe1.25 Ni0.75) O7−δ: A combined experimental and theoretical investigation
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2018 (English)In: Physical Review Materials, E-ISSN 2475-9953, Vol. 2, no 4, article id 044005Article in journal (Refereed) Published
Abstract [en]

We present a comprehensive study of the magnetic properties of Sr3-xYx(Fe1.25Ni0.75)O-7(-delta )(0 <= x <= 0.75). Experimentally, the magnetic properties are investigated using superconducting quantum interference device (SQUID) magnetometry and neutron powder diffraction (NPD). This is complemented by a theoretical study based on density functional theory as well as the Heisenberg exchange parameters. Experimental results show an increase in the Ned temperature (T-N) with an increase of Y concentrations and O occupancy. The NPD data reveal that all samples are antiferromagnetically ordered at low temperatures, which has been confirmed by our theoretical simulations for the selected samples. Our first-principles calculations suggest that the three-dimensional magnetic order is stabilized due to finite interlayer exchange couplings. The latter give rise to finite interlayer spin-spin correlations, which disappear above T-N.

Place, publisher, year, edition, pages
American Physical Society, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:oru:diva-66838 (URN)10.1103/PhysRevMaterials.2.044005 (DOI)000430385300001 ()
Funder
Swedish Research Council
Note

Funding Agencies:

eSSENCE  

KAW Foundation 

Available from: 2018-05-02 Created: 2018-05-02 Last updated: 2018-09-04Bibliographically approved
Huang, S., Holmstrom, E., Eriksson, O. & Vitos, L. (2018). Mapping the magnetic transition temperatures for medium- and high-entropy alloys. Intermetallics (Barking), 95, 80-84
Open this publication in new window or tab >>Mapping the magnetic transition temperatures for medium- and high-entropy alloys
2018 (English)In: Intermetallics (Barking), ISSN 0966-9795, E-ISSN 1879-0216, Vol. 95, p. 80-84Article in journal (Refereed) Published
Abstract [en]

Tailorable magnetic state near room temperature is very promising for several technological, including magnetocaloric applications. Here using first-principle alloy theory, we determine the Curie temperature (T-C) of a number of equiatomic medium- and high-entropy alloys with solid solution phases. All calculations are performed at the computed lattice parameters, which are in line with the available experimental data. Theory predicts a large crystal structure dependence of T-C, which explains the experimental observations under specified conditions. The sensitivity of the magnetic state to the crystal lattice is reflected by the magnetic exchange interactions entering the Heisenberg Hamiltonian. The analysis of the effect of composition on T-C allows researchers to explore chemistry-dependent trends and design new multi-component alloys with pre-assigned magnetic properties.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Curie temperature, High-entropy alloys, First-principle calculations, Monte-Carlo simulations
National Category
Metallurgy and Metallic Materials Physical Chemistry
Identifiers
urn:nbn:se:oru:diva-66647 (URN)10.1016/j.intermet.2018.01.016 (DOI)000428975100010 ()2-s2.0-85041415212 (Scopus ID)
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research VINNOVA, 2014-03374Swedish Energy AgencyCarl Tryggers foundation
Note

Funding Agencies:

Swedish Foundation for International Cooperation in Research and Higher Education

China Scholarship Council  

Hungarian Scientific Research Fund  OTKA 109570 

Available from: 2018-04-19 Created: 2018-04-19 Last updated: 2018-04-19Bibliographically approved
Thonig, D., Kvashnin, Y., Eriksson, O. & Pereiro, M. (2018). Nonlocal Gilbert damping tensor within the torque-torque correlation model. Physical Review Materials, 2(1), Article ID 013801.
Open this publication in new window or tab >>Nonlocal Gilbert damping tensor within the torque-torque correlation model
2018 (English)In: Physical Review Materials, ISSN 2475-9953, Vol. 2, no 1, article id 013801Article in journal (Refereed) Published
Abstract [en]

An essential property of magnetic devices is the relaxation rate in magnetic switching, which depends strongly on the damping in the magnetization dynamics. It was recently measured that damping depends on the magnetic texture and, consequently, is a nonlocal quantity. The damping enters the Landau-Lifshitz-Gilbert equation as the phenomenological Gilbert damping parameter a, which does not, in a straightforward formulation, account for nonlocality. Efforts were spent recently to obtain Gilbert damping from first principles for magnons of wave vector q. However, to the best of our knowledge, there is no report about real-space nonlocal Gilbert damping aij. Here, a torque-torque correlation model based on a tight-binding approach is applied to the bulk elemental itinerant magnets and it predicts significant off-site Gilbert damping contributions, which could be also negative. Supported by atomistic magnetization dynamics simulations, we reveal the importance of the nonlocal Gilbert damping in atomistic magnetization dynamics. This study gives a deeper understanding of the dynamics of the magnetic moments and dissipation processes in real magnetic materials. Ways of manipulating nonlocal damping are explored, either by temperature, materials doping, or strain.

Place, publisher, year, edition, pages
American Physical Society, 2018
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:oru:diva-64122 (URN)10.1103/PhysRevMaterials.2.013801 (DOI)000419105000001 ()
Funder
Swedish Research Council
Note

Funding Agencies:

eSSENCE  

KAW Foundation  2012.0031  2013.0020 

Available from: 2018-01-15 Created: 2018-01-15 Last updated: 2018-01-15Bibliographically approved
Eriksson, O. (2018). Searching for materials with reduced dimension. Nature Nanotechnology, 13(3), 180-181
Open this publication in new window or tab >>Searching for materials with reduced dimension
2018 (English)In: Nature Nanotechnology, ISSN 1748-3387, E-ISSN 1748-3395, Vol. 13, no 3, p. 180-181Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:oru:diva-64915 (URN)10.1038/s41565-017-0060-4 (DOI)000427009000007 ()29402978 (PubMedID)2-s2.0-85041617757 (Scopus ID)
Available from: 2018-02-08 Created: 2018-02-08 Last updated: 2018-04-03Bibliographically approved
Schmitz-Antoniak, C., Schmitz, D., Warland, A., Darbandi, M., Haldar, S., Bhandary, S., . . . Wende, H. (2018). Suppression of the Verwey Transition by Charge Trapping. Annalen der Physik, 530(3), Article ID 1700363.
Open this publication in new window or tab >>Suppression of the Verwey Transition by Charge Trapping
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2018 (English)In: Annalen der Physik, ISSN 0003-3804, E-ISSN 1521-3889, Vol. 530, no 3, article id 1700363Article in journal (Refereed) Published
Abstract [en]

The Verwey transition in Fe3O4 nanoparticles with a mean diameter of 6.3 nm is suppressed after capping the particles with a 3.5 nm thick shell of SiO2. By X-ray absorption spectroscopy and its associated X-ray magnetic circular dichroism this suppression can be correlated to localized Fe2+ states and a reduced double exchange visible in different site-specific magnetization behavior in high magnetic fields. The results are discussed in terms of charge trapping at defects in the Fe3O4/ SiO2 interface and the consequent difficulties in the formation of the common phases of Fe3O4. By comparison to X-ray absorption spectra of bare Fe3O4 nanoparticles in course of the Verwey transition, particular changes in the spectral shape could be correlated to changes in the number of unoccupied d states for Fe ions at different lattice sites. These findings are supported by density functional theory calculations.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
magnetite, nanoparticles, Verwey transition, X-ray absorption spectroscopy
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:oru:diva-66576 (URN)10.1002/andp.201700363 (DOI)000428350500010 ()2-s2.0-85042457108 (Scopus ID)
Note

Funding Agencies:

BMBF  05 ES3XBA/5 

DFG  WE 2623/3-1 

Helmholtz Association (Young Investigator's Group Borderline Magnetism)  VH-NG-1031 

Available from: 2018-04-13 Created: 2018-04-13 Last updated: 2018-09-04Bibliographically approved
Herper, H. C., Ahmed, T., Wills, J. M., Di Marco, I., Björkman, T., Iusan, D., . . . Eriksson, O. (2017). Combining electronic structure and many-body theory with large databases: A method for predicting the nature of 4 f states in Ce compounds. Physical Review Materials, 1(3), Article ID 033802.
Open this publication in new window or tab >>Combining electronic structure and many-body theory with large databases: A method for predicting the nature of 4 f states in Ce compounds
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2017 (English)In: Physical Review Materials, ISSN 2475-9953, Vol. 1, no 3, article id 033802Article in journal (Refereed) Published
Abstract [en]

Recent progress in materials informatics has opened up the possibility of a new approach to accessing properties of materials in which one assays the aggregate properties of a large set of materials within the same class in addition to a detailed investigation of each compound in that class. Here we present a large scale investigation of electronic properties and correlated magnetism in Ce-based compounds accompanied by a systematic study of the electronic structure and 4f-hybridization function of a large body of Ce compounds. We systematically study the electronic structure and 4f-hybridization function of a large body of Ce compounds with the goal of elucidating the nature of the 4f states and their interrelation with the measured Kondo energy in these compounds. The hybridization function has been analyzed for more than 350 data sets (being part of the IMS database) of cubic Ce compounds using electronic structure theory that relies on a full-potential approach. We demonstrate that the strength of the hybridization function, evaluated in this way, allows us to draw precise conclusions about the degree of localization of the 4f states in these compounds. The theoretical results are entirely consistent with all experimental information, relevant to the degree of 4f localization for all investigated materials. Furthermore, a more detailed analysis of the electronic structure and the hybridization function allows us to make precise statements about Kondo correlations in these systems. The calculated hybridization functions, together with the corresponding density of states, reproduce the expected exponential behavior of the observed Kondo temperatures and prove a consistent trend in real materials. This trend allows us to predict which systems may be correctly identified as Kondo systems. A strong anticorrelation between the size of the hybridization function and the volume of the systems has been observed. The information entropy for this set of systems is about 0.42. Our approach demonstrates the predictive power of materials informatics when a large number of materials is used to establish significant trends. This predictive power can be used to design new materials with desired properties. The applicability of this approach for other correlated electron systems is discussed.

Place, publisher, year, edition, pages
American Physical Society, 2017
National Category
Other Physics Topics
Identifiers
urn:nbn:se:oru:diva-63345 (URN)10.1103/PhysRevMaterials.1.033802 (DOI)000416568900002 ()
Funder
Swedish Research Council
Note

Funding Agencies:

KAW  2013.0020  2012.0031  2013.0096 

eSSENCE  

STandUP  

UD DOE  E3B7 

Villum foundation 

Available from: 2017-12-13 Created: 2017-12-13 Last updated: 2018-08-13Bibliographically approved
Hedlund, D., Cedervall, J., Edström, A., Werwinski, M., Kontos, S., Eriksson, O., . . . Gunnarsson, K. (2017). Magnetic properties of the Fe5SiB2-Fe5PB2 system. Physical Review B, 96(9), Article ID 094433.
Open this publication in new window or tab >>Magnetic properties of the Fe5SiB2-Fe5PB2 system
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2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 9, article id 094433Article in journal (Refereed) Published
Abstract [en]

The magnetic properties of the compound Fe5Si1-xPxB2 have been studied, with a focus on the Curie temperature T-C, saturation magnetization MS, and magnetocrystalline anisotropy. Field and temperature dependent magnetization measurements were used to determine T-C(x) and M-S(x). The saturation magnetization at 10 K (300 K) is found to monotonically decrease from 1.11 MA/m (1.03 MA/m) to 0.97 MA/m (0.87 MA/m), as x increases from 0 to 1. The Curie temperature is determined to be 810 and 615 K in Fe5SiB2 and Fe5PB2, respectively. The highest T-C is observed for x = 0.1, while it decreases monotonically for larger x. The Curie temperatures have also been theoretically determined to be 700 and 660 K for Fe5SiB2 and Fe5PB2, respectively, using a combination of density functional theory and Monte Carlo simulations. The magnitude of the effective magnetocrystalline anisotropy was extracted using the law of approach to saturation, revealing an increase with increasing phosphorus concentration. Low-field magnetization vs temperature results for x = 0,0.1,0.2 indicate that there is a transition from easy-axis to easy-plane anisotropy with decreasing temperature.

Place, publisher, year, edition, pages
American Physical Society, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:oru:diva-61634 (URN)10.1103/PhysRevB.96.094433 (DOI)000411975700001 ()2-s2.0-85029933600 (Scopus ID)
Funder
Swedish Research Council
Note

Funding Agencies:

G. Gustafsson's foundation  

KAW Foundation  2013.0020  2012.0031 

EU Horizon program NOVAMAG  

Foundation of Polish Science grant HOMING  

European Union under the European Regional Development Fund 

Available from: 2017-10-18 Created: 2017-10-18 Last updated: 2018-08-07Bibliographically approved
Lüder, J., Schött, J., Brena, B., Haverkort, M. W., Thunström, P., Eriksson, O., . . . Kvashnin, Y. O. (2017). Theory of L-edge spectroscopy of strongly correlated systems. Physical Review B, 96(24), Article ID 245131.
Open this publication in new window or tab >>Theory of L-edge spectroscopy of strongly correlated systems
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2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 24, article id 245131Article in journal (Refereed) Published
Abstract [en]

X-ray absorption spectroscopy measured at the L edge of transition metals (TMs) is a powerful element selective tool providing direct information about the correlation effects in the 3d states. The theoretical modeling of the 2p -> 3d excitation processes remains to be challenging for contemporary ab initio electronic structure techniques, due to strong core-hole and multiplet effects influencing the spectra. In this work, we present a realization of the method combining the density-functional theory with multiplet ligand field theory, proposed in Haverkort et al. [Phys. Rev. B 85, 165113 (2012)]. In this approach, a single-impurity Anderson model (SIAM) is constructed, with almost all parameters obtained from first principles, and then solved to obtain the spectra. In our implementation, we adopt the language of the dynamical mean-field theory and utilize the local density of states and the hybridization function, projected onto TM 3d states, in order to construct the SIAM. The developed computational scheme is applied to calculate the L-edge spectra for several TM monoxides. A very good agreement between the theory and experiment is found for all studied systems. The effect of core-hole relaxation, hybridization discretization, possible extensions of the method as well as its limitations are discussed.

Place, publisher, year, edition, pages
American Physical Society, 2017
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:oru:diva-63964 (URN)10.1103/PhysRevB.96.245131 (DOI)000418573600012 ()2-s2.0-85039461569 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2013.0020 2012.0031Carl Tryggers foundation
Note

Funding Agency:

EUSpec COST

Available from: 2018-01-09 Created: 2018-01-09 Last updated: 2018-09-07Bibliographically approved
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