Highly complex magnetic behavior resulting from hierarchical phase separation in AlCo(Cr)FeNi high-entropy alloys

iScience, vol. 25, pp. 104047

Abstract

Magnetic high-entropy alloys (HEAs) are a new category of high-performance magnetic materials, with multicomponent concentrated compositions and complex multi-phase structures. Although there have been numerous reports of their interesting magnetic properties, there is very limited understanding about the interplay between their hierarchical multi-phase structures and the resulting magnetic behavior. We reveal for the first time the influence of a hierarchically decomposed B2 + A2 structure in an AlCo 0.5 Cr 0.5 FeNi HEA on the formation of magnetic vortex states within individual A2 (disordered BCC) precipitates, which are distributed in an ordered B2 matrix that is weakly ferromagnetic. Non-magnetic or weakly ferromagnetic B2 precipitates in large magnetic domains of the A2 phase, and strongly magnetic Fe-Co-rich interphase A2 regions, are also observed. These results provide important insight into the origin of coercivity in this HEA, which can be attributed to a complex magnetization process that includes the successive reversal of magnetic vortices.

Authors 11

1. Qianqian Lan corresponding

   Forschungszentrum Jülich · Ernst Ruska Centre · Tsinghua University

   Affiliation as printed

   Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

   School of Materials Science and Engineering, Tsinghua University, Beijing 100086, China

2. András Kovács corresponding

   Forschungszentrum Jülich · Ernst Ruska Centre

   Affiliation as printed

   Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

3. Jan Caron

   Forschungszentrum Jülich · Ernst Ruska Centre

   Affiliation as printed

   Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

4. Hongchu Du Aachen Central Facility for Electron Microscopy

   Forschungszentrum Jülich · Ernst Ruska Centre · RWTH Aachen University

   Affiliation as printed

   Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen, Germany

   Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

5. Dongsheng Song

   Forschungszentrum Jülich · Ernst Ruska Centre

   Affiliation as printed

   Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

6. Sriswaroop Dasari

   University of North Texas

   Affiliation as printed

   Department of Materials Science and Engineering, University of North Texas, Denton, TX 76201, USA

7. Bharat Gwalani

   University of North Texas

   Affiliation as printed

   Department of Materials Science and Engineering, University of North Texas, Denton, TX 76201, USA

8. Varun Chaudhary

   Nanyang Technological University

   Affiliation as printed

   School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore

9. Raju V. Ramanujan

   Nanyang Technological University

   Affiliation as printed

   School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore

10. Rajarshi Banerjee

    University of North Texas · Nanyang Technological University

    Affiliation as printed

    Department of Materials Science and Engineering, University of North Texas, Denton, TX 76201, USA

    School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore

11. Rafal E. Dunin‐Borkowski

    Forschungszentrum Jülich · Ernst Ruska Centre

    Affiliation as printed

    Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany