Magnetic properties of Y2Fe17−x Gax and Sm2Fe17−xGax compounds

The magnetic properties of Y2Fe17−x Gax and Sm2Fe17−xGax for 3 ≤ x ≤ 7 have been investigated using the 57Fe Mo¨ ssbauer spectroscopy at room temperature. These compounds have the rhombohedral Th2Zn17 structure. X-ray diffraction analyses of aligned powders show that the easy direction of magnetization is parallel to the c-axis in Y2Fe10Ga7 and Sm2Fe14Ga3 and is perpendicular to the c-axis in Y2Fe14Ga3, Y2Fe12Ga5, Sm2Fe12Ga5 and Sm2Fe10Ga7. Mo¨ ssbauer studies indicate that all the samples studied are ferromagnetically ordered. The 57Fe hyperfine field decreases with increasing Ga content. This decrease results from the decreased magnetic exchange interactions resulting from Ga substitution. The average isomer shift, δ, for Y2Fe17−xGax and Sm2Fe17−xGax at room temperature is positive and the magnitude of δ increases with increasing Ga content. C 2005 Springer Science + Business Media, Inc.