七种非晶铁磁合金的体积磁致伸缩研究

 强制体积磁致伸缩的数量级极小（10^-10~10^-9(10³/4π)(A/m)]^-1），如通过测量三个互成直角方向的线磁致伸缩（10^-6(10³/4π)(A/m)]^-1）再正负迭加则很难测准。本文利用热力学关系：(dω/dH)_T,p=-(dM_s/dp)_T,H，用静水压法在0.000 1~2.4 GPa范围测得七种非晶合金Fe_81.6Si_4.6B_13.8、Fe_46.3Co_0.03Ni_46.5Si_3.75V_0.92B_2.5、Fe₇₅Cr₅Si₅B₁₅、Fe_73.9Co_8.3Si_4.4B_13.4、Fe₇₅Ni₅Si₅B₁₅、Fe_78.75Cu_1.25Si₅B₁₅和(Fe_0.85Co_0.15)₈₂Cu_0.4Si_4.4B_13.2的强制体积磁致伸缩及其随静水压p的变化。结果表明：（1）其中六种属于第一类压磁效应。(dω/dH)_T,p在大部分压力下为正，p增加时M_s不断减小；(dω/dH)_T,p仅在几个狭窄的压力范围为负。可归因于磁性原子与非磁性原子的化学短程序在压力下的变化。（2）非晶合金Fe_78.75Cu_1.25Si₅B₁₅属于第二类压磁效应。(dω/dH)_T,p在绝大部分压力下为负。M_s反常升高与Cu的特殊作用有关。

HYDROSTATIC PRESSURE DEPENDENCE OF FORCED VOLUME MAGNETOSTRICTION OF SEVEN AMORPHOUS ALLOYS

Forced volume magnetostriction is too minute 10^-10~10^-9(10³/4π)(A/m)]^-1 to be measured accurately by repeated addition of linear magnetostriction 10^-6(10³/4π)(A/m)]^-1. According to thermodynamic relation, (dω/dH)_T,p=-(dM_s/dp)_T,H ,we measured the M_s-p curve and obtained the hydrostatic pressure dependence of forced volume magnetostriction of seven amorphous alloys－Fe_81.6Si_4.6B_13.8, Fe_46.3Co_0.03Ni_46.5Si_3.75V_0.92B_2.5, Fe₇₅Cr₅Si₅B₁₅, Fe_73.9Co_8.3Si_4.4B_13.4, Fe₇₅Ni₅Si₅B₁₅, Fe_78.75Cu_1.25Si₅B₁₅ and (Fe_0.85Co_0.15)₈₂Cu_0.4Si_4.4B_13.2 in the range from 0.000 1 to 2.4 GPa. The results show clearly two kinds. (1) Six of them belong to the first type of pressure effect on magnetism. (dω/dH)_T,p is positive under most of pressure, i. e. M_s diminishes when p increases. (dω/dH)_T,p is negative only in some narrow ranges of pressure. It is due to variation of chemical short range order which is composed of magnetic atoms and non-magnetic atoms under different pressure. (2) Amorphous alloy Fe_78.75Cu_1.25Si₅B₁₅ belongs to the second type of pressure effect on magnetism. (dω/dH)_T,p is negative under most of pressure. Anomalous rise of M_s is related to the special role of Cu.