Magnetic Properties and Microstructure of W, La Added Sm₂Fe₁₇N₃ Powders

Abstract

The magnetic properties and microstructure of the W and/or La added Sm-Fe-N magnetic powders were investigated. The W and La+W added Sm-Fe-N powders exhibited higher coercivity of 2.1 and 2.0 MAm^-1 than that of the powder without La and W addition (1.5 MAm^-1), respectively, while the La added powder had lower coercivity of 1.0 MAm^-1. Initial recoil curves of each powders indicated that volume fraction of single domain particles was higher in the W and La+W added powders than in the La added powder, and the coercivity of these powders strongly depended on particles size. The lattice constant slightly changed with La and W addition. Microstructural observation revealed that W tended to condense in the small particle, and the W was detected from Sm₂Fe₁₇N₃(01̄1) plane.