非晶态合金的自旋波激发与结构涨落及超精细场分布

Spin-wave Excitation and Structure Fluctuations and Hyperfine Field Distribution of Amorphous Alloys

本文研究了非晶态（ａ）Ｆｅ－ＴＭ－Ｓｉ－Ｂ（ＴＭ＝Ｃｏ，Ｓｉ，Ｍｏ，Ｎｂ）合金从１．５Ｋ到３００Ｋ的磁化强度及室温穆斯堡尔谱，得到了居里温度Ｔ_Ｃ、饱和磁化强度σ_ｓ（０）、自旋波劲度常数Ｄ及平均超精细场等，结果表明，（ａ）对于Ｆｅ_（８３）Ｓｉ_５Ｂ_（１２），当Ｎｂ、ＭＯ与Ｓｉ、Ｃｏ取代Ｆｅ后，Ｆｅ－（ＮｂＭｏ）－Ｓｉ－Ｂ的磁性质不同于Ｆｅ－（Ｓｉ，Ｃｏ）－Ｓｉ－Ｂ；（ｂ）ａ－Ｆｅ－（Ｍｏ，Ｎｂ，Ｃｒ，Ｗ，Ｍｎ）－Ｍ（类金属）合金的Ｄ与Ｔｃ较好地满足了Ｄ＝ｍＴｃ的关系，其中ｍ的实验值接近于理论值，这表明合金中原子间的磁相互作用主要由近邻的自旋耦合所决定；（ｃ）从自旋波激发、Ｈａｎｄｒｉｃｈ关系及超精细场分布得到了结构涨落δ、δ’和δ”，比较它们，发现δ和δ’相当吻合，δ”基本上反映了δ的变化，这些表明了非晶态合金的自旋波与结构涨落及超精细场分布密切相关。

Amorphous Fe-TM-Si-B(TM =Co,Si,Mo,Nb) alloys have been studied by Mossbauer spectroscopy and by magnetizations from 1.5K～300K.Curie temperature Tc.spontaneous magnetization σ_s,spin wave stiffness constant D,average hyperfine field B_hf and so on have been obtained.The results are described as follows:(a) in amorphous Fe_(83)Si_5B_(12)alloy, when Mo(Nb) and Co(Si) substitute as Fe, the magnetic properties of Fe-( Mo, Nb)-Si-B alloys are different from Fe-(Co, Si)-Si-B alloys,(b) the relation between D and T_c ina-Fe-(Mo, Nb. Cr,W,Mn) based alloys is quite contented with the Eq. D = mT_c,where the experimental m value concides with m value calculated by the theory,which means that the range of direct Heisenberg ferromagnetic exchange interaction is confined to the nearest neighbours only,(c) from three different theories(spin wave stiffness relation,Handrich relation and hyperfine field distribution),the structure fluctuation δ,δ',δ',can be obtained. By comparing with δ,δ' and δ',it is found that the values of δ coincide essentially with ones of δ'and δ' for those alloys. Which means that the spin wave excitation of amorphous alloys are closely correlated to the structure fluctuation and hyperfine field distribution.