Magnetic properties of R2Fe17−xGax (R=Y and Gd) compounds

The magnetic properties of Y2Fe17−xGax for 3≤x≤7 and Gd2Fe17−xGax for 5≤x≤7 have been investigated using 57Fe Mössbauer spectroscopy. These compounds have the rhombohedral Th2Zn17 structure. X-ray diffraction analysis of aligned powders shows that the easy direction of magnetization is parallel to the c-axis in Y2Fe10Ga7 and Gd2Fe10Ga7 and is perpendicular to the c-axis in Y2Fe14Ga3, Y2Fe12Ga5, Gd2Fe12Ga5 and Gd2Fe11Ga6. Mössbauer studies indicate that those samples are ordered ferromagnetically. 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 R2Fe17−xGax (R=Y and Gd) at room temperature is positive and the magnitude of δ increases with increasing Ga content.