Intrinsic magnetic properties of Sm(Fe1-xCox)11Ti and Zr-substituted Sm1-yZry(Fe0.8Co0.2)11.5Ti0.5 compounds with ThMn12 structure toward the development of permanent magnets

Abstract

Constituent phases in Sm(Fe1-xCox)11Ti alloys with 0 ≤ x ≤ 0.3 and Sm1-yZry(Fe0.8Co0.2)11.5Ti0.5 alloys with 0 ≤ y ≤ 0.3 and the intrinsic magnetic properties of the ThMn12-type phases in these alloys were investigated for discussing the potential as permanent magnet material. The increase of Co substitution for Fe from x = 0.1 to 0.3 for Sm(Fe1-xCox)11Ti increases the saturation magnetization (μ0Ms) of the ThMn12-type compound from 1.35 T to 1.52 T, while the largest magnetic anisotropy field (μ0HA) of 10.9 T was achieved for x = 0.2, μ0Ms and Curie temperature (Tc) which were determined to be 1.43 T and 800 K, respectively. For the Sm1-yZry(Fe0.8Co0.2)11.5Ti0.5 alloy with lower Ti, the phase stability of the ThMn12 structure is attained by substituting Sm with Zr. Increase of Zr in Sm1-yZry(Fe0.8Co0.2)11.5Ti0.5 from y = 0.1 to 0.3 decreases μ0Ms from 1.61 to 1.52 T. However, the largest Tc of 830 K was found for the ThM12-type phase in the (Sm0.8Zr0.2) (Fe0.8Co0.2)11.5Ti0.5 alloy, μ0Ms and μ0HA of which were determined to be 1.53 T and 8.4 T at 300 K, respectively. The ThMn12-type phase in the (Sm0.8Zr0.2) (Fe0.8Co0.2)11.5Ti0.5 alloy has comparable intrinsic hard magnetic properties with those of Nd2Fe14B.