Importance of doping and frustration in itinerant Fe-doped Cr₂Al

Journal Article · Tue May 12 00:00:00 EDT 2015 · Journal of Magnetism and Magnetic Materials

DOI:https://doi.org/10.1016/j.jmmm.2015.05.024· OSTI ID:1185923

Susner, M. A. ^[1]; Parker, D. S. ^[1]; Sefat, A. S. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

We performed an experimental and theoretical study comparing the effects of Fe-doping of Cr₂Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr_1-xFe_x)₂Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing T_N to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x≈0.125 after which point increasing paramagnetic behavior is exhibited. Moreover, this is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which T_N gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculations explain that the Cr₂Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr₂Al. In pure-phase Cr₂Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr₂Al and Fe-doped Cr₂Al.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1185923
• Alternate ID(s): OSTI ID: 1247834
• Journal Information: Journal of Magnetism and Magnetic Materials, Vol. 392, Issue C; ISSN 0304-8853
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE