X-RAY-DIFFRACTION AND MAGNETIZATION STUDIES ON SM2FE17 AND ITS NITRIDES

Structural and magnetic characterizations of the Sm2Fe17Nx system with x = 0, 0.3, 0.7, 1.3, 1.8, 2.3, and 2.6 are presented. The pure Sm2Fe 17 parent phase crystallizes in the Th2Zn17-like rhombohedral structur e, as does 'completely nitrided' Sm2Fe17N2.6. Samples with N content 1 .3 less than or equal to x less than or equal to 2.3 clearly show a tw o-phase structure, having both an unnitrided phase and a nitrided phas e, with the nitrided phase possessing larger lattice parameters. The x = 0.3 sample does not show any nitrided phase, and has magnetic behav ior unlike the samples with higher N content. As discussed, it appears that the N atoms which are initially introduced might occupy vacancie s, grain boundaries, or sites other than the octahedral interstitial s ites as originally proposed.