摘要
The crystallographic and magnetic structures of Er2Fe15Al2 and Er2Fe12Al5 have been refined in Gaussian peak-shape by Rietveld analysis of Neutron diffrac- tion data. The refined results indicated that Er2Fe15Al2 compound has Th2Ni17-type hexagonal structure （space group: P63/mmc） and Er2Fe12Al5 has Th2Zn17-type rhom- bohedral structure （space group:R 3m）. The Al atoms prefer 12j and 12k sites with occupancies 0.21 and 0.13, respectively, in Er2Fe15Al2 and prefer 18f, 18h and 6c sites with occupancies 0.35, 0.36 and 0.37, respectively, in Er2Fe12Al5. The magnetic mo- ments of all Fe atoms display ferromagnetically arrangement and the moments of Er atoms couple ferrimagnetically to the moments of the Fe atoms. The moments lie in the plane perpendicular to the six-fold axis and exhibit planar magnetic anisotropy in both samples. The values of To were given and the neutron refined results coincide with that of the magnetic measurements. The relation between magnetic properties and structures was discussed.
The crystallographic and magnetic structures of Er_2Fe_(15)Al_2 and Er_2Fe_(12)Al_5 have been refined in Gaussian peak-shape by Rietveld analysis of Neutron diffrac- tion data. The refined results indicated that Er_2Fe_(15)Al_2 compound has Th_2Ni_(17)-type hexagonal structure (space group: P6_3/mmc) and Er_2Fe_(12)Al_5 has Th_2Zn_(17)-type rhom- bohedral structure (space group:R 3m). The Al atoms prefer 12j and 12k sites with occupancies 0.21 and 0.13, respectively, in Er_2Fe_(15)Al_2 and prefer 18f, 18h and 6c sites with occupancies 0.35, 0.36 and 0.37, respectively, in Er_2Fe_(12)Al_5. The magnetic mo- ments of all Fe atoms display ferromagnetically arrangement and the moments of Er atoms couple ferrimagnetically to the moments of the Fe atoms. The moments lie in the plane perpendicular to the six-fold axis and exhibit planar magnetic anisotropy in both samples. The values of To were given and the neutron refined results coincide with that of the magnetic measurements. The relation between magnetic properties and structures was discussed.
基金
Nuclear Industry Science Foundation !(H7196B0109)
National Nature Science Foun dation of China (19835050)
