Abstract: A series of YTi(Fe_(1-x)_(11)alloy with x=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 has been investigated by measurement of the structural properties and ~(57)Fe M(?)ssbauer experiments.The pure ThMn_(12)-structure phase exists at x≤0.03 and is absent at x>0.03.The reasons for lower satura- tion magnetization and lower energy product of the ThMn_(12)-structure compounds were given.The crystal structure relations between R_2Fe_(17)-structure and ThMn_(12)-structure were discussed.Comparing with the R_2Fe_(17)and R_2Fe_(14)B compounds,the ThMn_(12)-structure RFe_(12-x)M_x compounds have the same magnetic moment of Fe at x=0.The potential for increasing the saturation magnetization of ThMn_(12)-structure compounds may be enhanced by the addition of stabilization elements.

Key words: ThMn_(12)-structure stability, magnetic properties, crystal structure