Highly complex magnetic behavior resulting from hierarchical phase separation in AlCo(Cr)FeNi high-entropy alloys
Qianqian Lan,
András Kovács,
Jan Caron,
Hongchu Du,
Dongsheng Song,
Sriswaroop Dasari,
Bharat Gwalani,
Varun Chaudhary,
Raju V. Ramanujan,
Rajarshi Banerjee,
Rafal E. Dunin-Borkowski
Affiliations
Qianqian Lan
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; Corresponding author
András Kovács
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Corresponding author
Jan Caron
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
Hongchu Du
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen, Germany
Dongsheng Song
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
Sriswaroop Dasari
Department of Materials Science and Engineering, University of North Texas, Denton, TX 76201, USA
Bharat Gwalani
Department of Materials Science and Engineering, University of North Texas, Denton, TX 76201, USA
Varun Chaudhary
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
Raju V. Ramanujan
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
Rajarshi Banerjee
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
Rafal E. Dunin-Borkowski
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
Summary: 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 AlCo0.5Cr0.5FeNi 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.
