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

Autor: 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
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: iScience, Vol 25, Iss 4, Pp 104047- (2022)
Druh dokumentu: article
ISSN: 2589-0042
DOI: 10.1016/j.isci.2022.104047
Popis: 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.
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