The structure and magnetic properties of Gd2Co17-xMnx (x=0-4) compounds

X-Ray diffraction (XRD) and magnetization measurements were employed to inv estigate the effect of substitution of Mn for Co on the structure and magne tic properties of Gd2Co17-xMnx (x = 0-4) compounds. XRD patterns show that all samples are single phase with rhombohedral Th2Zn17-type structure. The substitution of Mn for Co leads to a monotonic increase in unit cell volume . The saturation magnetization increases slightly for x less than or equal to2, then decreases slowly. The Curie temperature T-C is found to decrease monotonically with increasing Mn concentration. The samples with x = 1-4 ex hibit a uniaxial anisotropy at room temperature as determined from the XRD measurement on magnetically aligned samples. The magnetocrystalline anisotr opy field H, increases with increasing Mn concentration, attaining a maximu m value of 43.7 kOe at x = 4. Spin reorientation phenomena are observed in Gd2Co17 and off-stoichiometric Gd2Co17 compounds, which may be due to the d ifferent temperature dependence of the anisotropy of the Co sites. (C) 2001 Elsevier Science B.V. Ah rights reserved.