Crystal structure and magnetic properties of Nd（Mn1-xFex）2Si2 compounds

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 I4/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.

Crystal structure and magnetic properties of Nd(Mn1-xFex)2Si2 compounds

X-ray powder diffraction, resistivity and magnetizationstudies have been performed on polycrystalline Nd(Fe_xMn_1- x)₂Si₂ (0 ≤ x ≤ 1) compounds which crystallize ina ThCr₂Si₂-type structure with the space group I4/mmm.The field-cooled temperature dependence of the magnetization curvesshows that, at low temperatures, NdFe₂Si₂ isantiferromagnetic, while the other compounds show ferromagneticbehaviour. The substitution of Fe for Mn leads to a decrease inlattice parameters a, c and unit-cell volume V. The Curietemperature of the compounds first increases, reaches a maximumaround x=0.7, then decreases with Fe content. However, thesaturation magnetization decreases monotonically with increasing Fecontent. This Fe concentration dependent magnetization ofNd(Fe_xMn_1-x)₂Si₂ compounds can be well explainedby taking into account the complex effect on magnetic properties dueto the substitution of Mn by Fe. The temperature's square dependence onelectrical resistivity indicates that the curve ofNd(Fe_0.6Mn_0.4)₂Si₂ has a quasi-linear characterabove its Curie temperature, which is typical of simple metals.