Magnetic properties and structural characteristics of interstitially modified Nd3(Fe1−xCox)27.7Ti1.3Ny nitrides (x=0.1, 0.2, 0.3, 0.4)

Abstract Formation and magnetic properties of the interstitial Nd 3 (Fe,Ti) 29 -type nitrides were investigated for Nd 3 (Fe 1− x Co x ) 27.7 Ti 1.3 over the concentration range 0 x ⩽0.4. The decomposition temperature T d decreases with increasing Co content x . The relative lattice expansion upon nitrogenation is 4.6–4.9% indicating 3.5–3.7 N-atoms per formula unit. Upon nitrogenation the Curie temperature values increase with Co, but the increase rate is slower compared to that of the parent compounds. For x =0.1, 0.2 a complex magnetic anisotropy is observed, whereas, for x =0.3 and 0.4 the compounds present uniaxial anisotropy with an easy magnetisation direction along the [4 0 −2] direction. The increase of the average hyperfine field by substituting Co for Fe in Nd 3 (Fe 1− x Co x ) 27.7 Ti 1.3 N y is rather small and the position of the maximum ( x =0.1) at room temperature is closer to Fe than for the parent compounds (at least x =0.4).