Spin reorientation and magnetoelastic coupling in Tb₆Fe_1-xCo_xBi₂ (x = 0, 0.125, 0.25, 0.375) alloy system

Journal Article · Sat Jul 05 00:00:00 EDT 2014 · Journal of Alloys and Compounds

DOI:https://doi.org/10.1016/j.jallcom.2014.06.183· OSTI ID:1265275

Koehler, Michael R. ^[1]; Garlea, Vasile O. ^[2]; McGuire, Michael A. ^[2]; Jia, Lin ^[1]; Keppens, Veerle ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Tb₆FeBi₂ adopts a noncentrosymmetric crystal structure and orders ferromagnetically at T_C1 = 250 K with an additional magnetic transition at T_C2 = 60 K. The low temperature magnetoelastic response in this material is strong, and is enhanced by cobalt substitution. In this paper, the temperature dependence of the atomic and magnetic structure of Tb₆Fe_1-xCo_xBi₂ (x = 0, 0.125, 0.25, and 0.375) is reported from powder X-ray diffraction (XRD) and powder neutron diffraction (PND) measurements. Below the Néel temperature a ferrimagnetic ordering between the terbium and iron moments exists in all compounds studied. Related to the enhanced magnetostructural response, the Co-doped compounds undergo a crystallographic phase transition below about 60 K. This transition also involves a canting of the magnetic moments away from the c-axis. The structural transition is sluggish and not fully completed in the parent Tb₆FeBi₂ compound, where a mixture of monoclinic and hexagonal phases is identified below 60 K. Lastly, the spin reorientation transition is discussed in terms of competing exchange interactions and magnetocrystalline anisotropies of the two Tb sites and Fe/Co sublattices.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1265275
• Alternate ID(s): OSTI ID: 1496339
• Journal Information: Journal of Alloys and Compounds, Vol. 615; ISSN 0925-8388
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Rare earth alloys and compounds
Neutron diffraction
Crystal structure