|Macro- and microscopic magnetic properties of rare earth element free permanent magnets|
|SweGRIDS research area||Materials for Power Grid and Storage|
|SweGRIDS project code||MTL2|
|Researcher||Henry Stopfel (webpage)|
|Project period||2018-08-20 to 2020-08-19|
|Project supervisor||Peter Svedlindh (webpage)|
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Höganäs AB has been involved in research and development of rare earth element free permanent magnets since 2012 and has been a SweGRIDS sponsoring industry since 2013. The project initially focused on Fe2P and Fe2B based magnets, but the interest was after some initial work shifted to Mn-based magnets, like MnAlC, MnAlB and MnBi. The objectives for participating groups at Uppsala University, including the group led by Martin Häggblad Sahlberg, have been to synthesize phase pure materials and to characterize the materials structurally and magnetically, while the focus for Höganäs AB has been up-scaled production and compaction and alignment of permanent magnet powder. The work has developed to a stage where single phase Mn-based permanent magnet powder can be produced with intrinsic magnetic properties surpassing the corresponding properties found in hard ferrites.
The next step in this project will be to decrease the powder particle size to a level where one particle corresponds to a single domain magnetic grain or to an assembly of grains with aligned magnetic anisotropy axes. The latter will require in-depth studies of powder microstructure combined with magnetic microstructure studies and magnetic domain imaging using Kerr and magnetic force microscopy. Once this has been achieved, the equipment developed at Höganäs AB for compaction and alignment of particle easy axes can be used to achieve permanent magnets with properties superior to those of hard ferrites.
Another objective will be to synthesize tetrataenite (L10-FeNi), which is another promising candidate for use as a rare earth element free permanent magnet. A recent publication shows that powders of this material can be synthesized using a combination of nitridation and heat treatments. While the group led by Martin Häggblad Sahlberg will be responsible for developing necessary synthesis routes, we will focus on characterizing the powders magnetically using methods yielding information about macro- as well as microscopic magnetic properties.
Summary of work
2018. Purchase and installation of a Scanning Probe Microscope for Atomic/Magnetic Force Microscopy. Designing of a magnetic stage for Magnetic Force Microscopy in magnetic fields and contacting the workshop to produce it. Initial structural and magnetic measurements on high entropy alloys.
2019. Fabrication of the magnetic stage for MFM measurements in magnetic fields, first trial measurements and improvement of the design, contacted workshop for possible changes. Investigations of the possibilities of micromagnetic simulations of MnAl and first calculations.
2020. Finalization of the magnetic stage for MFM measurements in magnetic fields, set back due to material breakage and therefore the need to redesign and fabricate parts of the magnetic stage. Continuation of the micromagnetic simulations of MnAl in Collaboration with the Theory devision. In-field magnetic force microscopy on MnAlC samples from Höganäs.
2018-06. Meeting with Höganäs AB and agreement on starting as a PostDoc.
2018-08. Partially installation of the new Dimension Icon system.
2018-10. Meeting with Höganäs AB and partners at Uppsala University and final installation of the Dimension Icon system.
2018-11. Meeting with Höganäs AB and partners at Uppsala University and finalization of the design of the magnetic stage for the Dimension Icon system.
2018-12. Contacted the workshop at Uppsala University to fabricate the magnetic stage.
2019-01. Meeting with Höganäs AB and Partners at Höganäs.
2019-02. Visiting the Mumax3 developer in Ghent, to get more insight into the micromagnetic simulations software.
2019-03. Purchasing a Computer for Mumax3 simulations and starting first simulations.
2019-04. Meeting with Höganäs AB and partners at Uppsala University and the magnet has been produced by the workshop and assembled by me. SweGRIDS conference in Stockholm.
2019-05. Sample stage for magnet has been ordered from workshop, as not delivered with the magnet.
2019-06. Meeting with Höganäs AB and partners at Uppsala University and sample stage was delivered from workshop.
2019-08. JEMS conference in Uppsala and first trials for measurements in magnetic fields have been performed.
2019-09. Meeting with Höganäs AB and partners at Uppsala University.
2019-10. Meeting with Höganäs AB and partners at Uppsala University and re-designing of the magnet to increase usability.
2019-11. First in-field measurements on MnAl-powder with the MFM and the magnetic stage.
2019-12. Contacted workshop on improvements on the magnetic stage.
2020-01. Meeting with Höganäs AB and partners at Uppsala University.
2020-02. Workshop finishes the updated design on the magnetic stage.
2020-03. Magnetic stage breaks during first trail experiments, workshop has to redo the whole moving part of the stage.
2020-03. Meeting with Höganäs AB and partners at Uppsala University.
2020-04. SweGRIDS annual conference got cancelled and our meetings shifted to Zoom-meetings, where Höganäs AB could not participate so often due to their reduced working time during the Pandemic.
2020-04. Workshop fixed the broken part of the magnetic stage with a much stronger solution, additional updates on the stage to reliable fix the magnetic field are requested from the workshop.
2020-04. First Zoom project meeting.
2020-05. Workshop fixed the updated design for the magnetic stage.
2020-06. Final fixes on the magnetic stage performed by the workshop.
2020-06. Zoom project meeting.
2020-07. First in-field experiments performed on MnAlC samples from Höganäs AB.
2020-08. Systematic measurements performed on 3 different gas atomized powder samples from Höganäs AB, each sample has a measurement time of 3 full weeks.
2020-10. Project financing ended, measured data still needs to be analyzed thoroughly.
2020-11. Digital SweGRIDS conference.
Doc. Martin Häggblad Sahlberg, UU
Prof. Olle Eriksson, UU
Rose-Marie Yttergren, Höganäs AB
Publications by this researcher
See alternatively the researcher's full DiVA list of publications, with options for sorting.
Publications in journals and conferences usually will not show until a while after they are published.
Magnetic properties and thermal stability of B2 and bcc phases in AlCoCrFeMnxNi
Simon R. Larsen, Daniel Hedlund, Henry Stopfel, Dennis Karlsson, Christian K. Christensen, Peter Svedlindh, Johan Cedervall.
2021, Journal of Alloys and Compounds, vol. 861
Copper-zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method
José Montero Amenedo, Tesfalem Welearegay, Jakob Thyr, Henry Stopfel, Tatjana Dedova, Ilona Oja Acik, Lars Österlund.
2021, RSC Advances, vol. 11(17)
Influence of nano-VC on the structural and magnetic properties of MnAlC-alloy
Vitalii Shtender, Henry Stopfel, Daniel Hedlund, Dennis Karlsson, Rajasekhar Pothala, Björn Skårman, Fredrik Olsson, Hilmar Vidarsson, Gabriella Andersson, Peter Svedlindh, Martin Sahlberg.
2021, Scientific Reports, vol. 11
Multiple energy scales in mesospin systems : The vertex-frustrated Saint George lattice
Henry Stopfel, Unnar B. Arnalds, Aaron Stein, Thomas P. A. Hase, Björgvin Hjörvarsson, Vassilios Kapaklis.
2021, Physical Review Materials, vol. 5(11)
Temperature-induced collapse of spin dimensionality in magnetic metamaterials
Björn Erik Skovdal, Nanny Strandqvist, Henry Stopfel, Merlin Pohlit, Tobias Warnatz, Samuel D. Slöetjes, Vassilios Kapaklis, Björgvin Hjörvarsson.
2021, Physical Review B, vol. 104(1)
Collective magnetic dynamics in artificial spin ice probed by ac susceptibility
Merlin Pohlit, Giuseppe Muscas, Ioan-Augustin Chioar, Henry Stopfel, Agne Ciuciulkaite, Erik Östman, Spyridon D. Pappas, Aaron Stein, Björgvin Hjörvarsson, Petra Jönsson, Vassilios Kapaklis.
2020, Physical Review B, vol. 101(13)
Insights into the Formation of DNA−Magnetic Nanoparticle Hybrid Structures : Correlations between Morphological Characterization and Output from Magnetic Biosensor Measurement
Reinier Oropesa Nunez, Teresa Zardán Gómez de la Torre, Henry Stopfel, Peter Svedlindh, Mattias Strömberg, Klas Gunnarsson.
2020, ACS Sensors, vol. 5(11)
Rigid Exchange Coupling in Rare-Earth-Lean Amorphous Hard/Soft Nanocomposites
Parul Rani, Giuseppe Muscas, Henry Stopfel, Gabriella Andersson, Petra Jönsson.
2020, Advanced Electronic Materials, vol. 6(11)
Impact of the crystal orientation on spin-orbit torques in Fe/Pd bilayers
Ankit Kumar, Nilamani Behera, Rahul Gupta, Sajid Husain, Henry Stopfel, Vassilios Kapaklis, Rimantas Brucas, Peter Svedlindh.
2020, Journal of Physics D: Applied Physics, vol. 53(35)
The influence of diameter on the magnetic saturation in Fe 84 Cu 16 /MgO  multilayered islands
Tobias Warnatz, Björn Erik Skovdal, Fridrik Magnus, Henry Stopfel, Daniel Primetzhofer, Aaron Stein, Rimantas Brucas, Björgvin Hjörvarsson.
2020, Journal of Magnetism and Magnetic Materials, vol. 496
Interaction modifiers in artificial spin ices
Erik Östman, Henry Stopfel, Ioan-Augustin Chioar, Unnar B. Arnalds, Aaron Stein, Vassilios Kapaklis, Björgvin Hjörvarsson.
2018, Nature Physics, vol. 14(4)
Magnetic order and energy-scale hierarchy in articial spin ice structures
Henry Stopfel, Erik Östman, Ioan-Augustin Chioar, David Greving, Unnar Arnalds, Thomas P. A. Hase, Aaron Stein, Björgvin Hjörvarsson, Vassilios Kapaklis.
2018, Physical Review B, vol. 98
Tailoring the magnetic order in mesoscopic spin systems
2017, Thesis (PhD), Acta Universitatis Upsaliensis, Digital 1574
Spin transfer torque ferromagnetic resonance induced spin pumping in the Fe/Pd bilayer system
Ankit Kumar, Serkan Akansel, Henry Stopfel, M. Fazlali, J. Åkerman, Rimantas Brucas, Peter Svedlindh.
2017, Physical Review B, vol. 95(6)
A new look on the two-dimensional Ising model : thermal artificial spins
Unnar B. Arnalds, Jonathan Chico, Henry Stopfel, Vassilios Kapaklis, Oliver Bärenbold, Marc A. Verschuuren, Ulrike Wolff, Volker Neu, Anders Bergman, Björgvin Hjörvarsson.
2016, New Journal of Physics, vol. 18
Thermally induced magnetic relaxation in square artificial spin ice
Mikael S. Andersson, Spyridon D. Pappas, Henry Stopfel, Erik Östman, A. Stein, Per Nordblad, Roland Mathieu, Björgvin Hjörvarsson, Vassilios Kapaklis.
2016, Scientific Reports, vol. 6
Magnetic properties of amorphous Fe93Zr7 films : Effect of light ion implantation
Atieh Zamani, Reda Moubah, Martina Ahlberg, Henry Stopfel, Unnar Arnalds, Anders Hallén, Björgvin Hjörvarsson, Gabriella Andersson, Petra Jönsson.
2015, Journal of Applied Physics, vol. 117(14)
Publication list last updated from DiVA on 2022-04-16 02:36.
Page started: 2018-08-20
Last generated: 2022-04-16