纳米FeAl合金的磁共振谱分析

MAGNETIC RESONANCE SPUCTRUM ANALYSIS IN NANOSTRUCTURED FeAl ALLOY 

在与晶粒组元相当的包裹纳米ＦｅＡｌ晶粒的无序界面或／和表面组元中，存在ＦｅＡｌＦｅ电子的超交换作用或／和ＦｅＦｅ交换作用，使多晶ＦｅＡｌ合金因晶粒纳米化出现非磁性—磁性转变．Ｘ波段（频率为９４８ＧＨｚ）的电子自旋共振（ＥＳＲ）实验表明多晶ＦｅＡｌ合金没有磁共振信号．纳米晶样品的铁磁共振（ＦＭＲ）信号是一个线宽ΔＨｐｐ为８×１０４Ａ／ｍ以上的宽峰．还观测到纳米晶体样品中Ｆｅ２＋离子的ＥＳＲ精细结构双峰，两峰间隔为１３１６×１０５Ａ／ｍ，每个峰的线宽ΔＨｐｐ小于８００Ａ／ｍ．顺磁性Ｆｅ２＋离子的组态为３ｄ５４ｓ１，自旋Ｓ＝１，其零磁场劈裂Ｄ为２４４８ＧＨｚ（或１０１２×１０－６ｅＶ）．顺磁性Ｆｅ２＋的ＥＳＲ双峰叠加在铁磁性的ＦＭＲ宽峰上形成ＦＭＲ谱线上的两个类似共振奇点的尖峰．

Abstract When the fraction of inordinate component on the interface or/and surface in nanostructured FeAl is comparable to that of crystal grain which is wrapped up in the former,and there exists Fe Al Fe surperexchange or/and Fe Fe exchange interactions in the inordinate component on the interface or/and surface, a nonmagnetism magnetism transition between polycrystall FeAl alloy and nanostructured FeAl would result.There was no signal of magnetic resonance in the bulk polycrystal FeAl from the experimental results of electron spin resonance (ESR) in X wave band with a frequancy of 9 48GHz.The ferromagnetic resonance (FMR) signals were observed in the nanostructured samples, whose line widths Δ H pp were over 8×10 4A/m.Otherwise, an ESR fine structural signal of double peaks of Fe 2+ ion was also observed in nanocrystal line samples, the interval of the two peaks was 1 316×10 5A/m,and the Δ H pp of each peak was smaller than 800A/m.The configuration of the paramagnetic Fe 2+ was 3d 54s 1, and spin quantum number was S =1,its zero field splitting D was 2 448GHz,or 10 12×10 -6 eV.An overlap of the ESR double peaks of paramagnetic Fe 2+ and the wide FMR peak resulted in two sharp peaks like resonant singularities on the FMR spectrum.