Assessment of off-stoichiometric Zr_33-xFe_52+xSi₁₅C14 Laves phase compounds as permanent magnet materials

Journal Article · 11 December 2017 · AIP Advances

DOI: https://doi.org/10.1063/1.5006488 · OSTI ID:1499158

Gabay, A. M.  ^[1]; Hadjipanayis, G. C. ^[1]

---

1. Univ. of Delaware, Newark, DE (United States)

Recently, Fe-based rare-earth-free compounds with non-cubic crystal structures were proposed as a base for permanent magnets which would not rely on critical elements. In this work, two series of alloys, Zr₂₇Fe_73-wSi_w (0 ≤ w ≤ 15) and Zr_{33- x}Fe_52+xSi₁₅ (0 ≤ x ≤ 11), were prepared and characterized after annealing at 1538 K in order to determine the fundamental magnetic properties of the C36 and C14 hexagonal Laves phase compounds. A mixture of the cubic C15 and Zr₆Fe₂₃ structures was observed instead of the expected C36 structure. The hexagonal C14 was found in all Zr_33-xFe_52+xSi₁₅ alloys with its lattice parameters linearly decreasing as the Fe(Si) atoms occupy the Zr sites in the Laves phase crystal structure. The solubility limit of Fe in the C14 structure at 1538 K corresponds to x = 9.5. The Curie temperature of the C14 compounds increases with deviation from the Laves phase stoichiometry from 290 K to 530 K. The room-temperature spontaneous magnetization also increases reaching, after correcting for the non-magnetic impurities, a value of 6.7 kG. The magnetocrystalline anisotropy of the off-stoichiometric C14 Laves phase was found to be uniaxial with the easy magnetization direction parallel to the hexagonal axis. Unfortunately, the anisotropy field, which does not exceed 10 kOe, is not sufficiently high to make the compounds interesting as permanent magnet materials.

• Research Organization: Univ. of Delaware, Newark, DE (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-90ER45413
• OSTI ID: 1499158
• Alternate ID(s): OSTI ID: 1412626
• Journal Information: AIP Advances, Vol. 8, Issue 5; ISSN 2158-3226
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English