非晶合金Fe₅₀Ni₃₀B₂₀的磁弛豫的低能激发

非晶合金Fe 50 Ni 30 B 20 的磁弛豫的低能激发 STUDY OF THE MAGNETIC RELAXATION FOR AMORPHOUS Fe 50 Ni 30 B 20 BY THE LOW ENERGY EXCITATION 田德诚 Tian Decheng 1 2 first-author 邹宪武 Zou Xianwu 1 2 金准智 Jin Zhunzhi 1 2 庄鸿章 Zhuang Hongzhang 1 2 武汉大学物理学系 武汉大学物理学系 Department of Physics, Wuhan University Department of Physics, Wuhan University 武汉大学物理学系,武汉,430072 武汉大学物理学系,武汉,430072 在双能级模型及凝聚态物质的低频涨落、耗散和弛豫行为的统一理论基础上,研究了非晶合金Fe 50 Ni 30 B 20 于480K退火2h以后,在250～350K范围的磁后效谱,计算得到红外发散指数n=0.11,特征弛豫时间τ x =2.8×10 -17 s。在弛豫峰温处,计算的表观激活能E A 为1.7eV,此结果与实验很好地一致。计算结果表明,对此非晶合金,磁后效是由于B原子跳跃引起Fe-B,Ni-B原子对的局域重排而导致的。此外,也讨论了随着温度上升激活能E A 增加的原因。 Basde on the two-level model and the unified theory of low frequency fluctua tion , dissipation and relaxation processes for condensed matter , we studied the magnetic afere ffect spectrum in the range between 250 and 350K for the amorphous Fe50Ni30B20 alloy after annealing treatment for 2 h at 480K. The calculated infred divergence exponent n = 0.11,and characteristic relaxation time t∞= 2. 8×l017s. The calculated apparent activation energy EA,at the temperature of the relaxation peak,is about 1. 7ev. They are in good agreement with experiments. The calculations support that for this amorphous alloy,the magnetic af-tereffects are caused by the local rearrangement of the alignment of atom pairs Fe-B and Ni-B as a resnlt of jumps of B atoms. It is discussed that activation energy EA increases with in-creasing temperature. 双能级模型 磁后效 激活能 红外发散 two-level model magnetic aftereffect activation energy infrared diver-gence O482.5 国家自然科学基金资助的课题 1994-05-01 2021-04-01 5