Magnetic properties of the CrMnFeCoNi high-entropy alloy

0478871 - ÚFM 2018 RIV US eng J - Journal Article
Schneeweiss, Oldřich - Friák, Martin - Dudová, Marie - Holec, D. - Šob, Mojmír - Kriegner, D. - Holý, V. - Beran, Přemysl - George, E. P. - Neugebauer, J. - Dlouhý, Antonín
Magnetic properties of the CrMnFeCoNi high-entropy alloy.
Physical Review B. Roč. 96, č. 1 (2017), č. článku 014437. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR(CZ) GA14-22834S; GA MŠMT(CZ) LQ1601
Institutional support: RVO:68081723 ; RVO:61389005
Keywords : high-entropy alloys * magnetism * low-temperatures * quantum-mechanical calculations * magnetic transitions
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Condensed matter physics (including formerly solid state physics, supercond.) (UFM-A); Condensed matter physics (including formerly solid state physics, supercond.) (UJF-V)
Impact factor: 3.813, year: 2017

We present experimental data showing that the equiatomic CrMnFeCoNi high-entropy alloy undergoes two magnetic transformations at temperatures below 100 K while maintaining its fcc structure down to 3 K. The first transition, paramagnetic to spin glass, was detected at 93 K and the second transition of the ferromagnetic type occurred at 38 K. Field-assisted cooling below 38 K resulted in a systematic vertical shift of the hysteresis curves. Strength and direction of the associated magnetization bias was proportional to the strength and direction of the cooling field and shows a linear dependence with a slope of 0.006±0.001 emuT. The local magnetic moments of individual atoms in the CrMnFeCoNi quinary fcc random solid solution were investigated by ab initio (electronic density functional theory) calculations. Results of the numerical analysis suggest that, irrespective of the initial configuration of local magnetic moments, the magnetic moments associated with Cr atoms align antiferromagnetically with respect to a cumulative magnetic moment of their first coordination shell. The ab initio calculations further showed that the magnetic moments of Fe and Mn atoms remain strong (between 1.5 and 2microB), while the local moments of Ni atoms effectively vanish. These results indicate that interactions of Mn- and/or Fe-located moments with the surrounding magnetic structure account for the observed macroscopic magnetization bias.
Permanent Link: http://hdl.handle.net/11104/0275597