X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/...X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/mmm. The field-cooled temperature dependence of the magnetization curves shows that, at low temperatures, NdFe2Si2 is antiferromagnetic, while the other compounds show ferromagnetic behaviour. The substitution of Fe for Mn leads to a decrease in lattice parameters a, c and unit-cell volume V. The Curie temperature of the compounds first increases, reaches a maximum around x=0.7, then decreases with Fe content. However, the saturation magnetization decreases monotonically with increasing Fe content. This Fe concentration dependent magnetization of Nd（FexMn1-x）2Si2 compounds can be well explained by taking into account the complex effect on magnetic properties due to the substitution of Mn by Fe. The temperature＇s square dependence on electrical resistivity indicates that the curve of Nd（Fe0.6Mn0.4）2Si2 has a quasi-linear character above its Curie temperature, which is typical of simple metals.展开更多
基金Project supported by the National Basic Research Program of China (Grant No 2006CB601101)
文摘X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/mmm. The field-cooled temperature dependence of the magnetization curves shows that, at low temperatures, NdFe2Si2 is antiferromagnetic, while the other compounds show ferromagnetic behaviour. The substitution of Fe for Mn leads to a decrease in lattice parameters a, c and unit-cell volume V. The Curie temperature of the compounds first increases, reaches a maximum around x=0.7, then decreases with Fe content. However, the saturation magnetization decreases monotonically with increasing Fe content. This Fe concentration dependent magnetization of Nd（FexMn1-x）2Si2 compounds can be well explained by taking into account the complex effect on magnetic properties due to the substitution of Mn by Fe. The temperature＇s square dependence on electrical resistivity indicates that the curve of Nd（Fe0.6Mn0.4）2Si2 has a quasi-linear character above its Curie temperature, which is typical of simple metals.
