摘要
在20～70K 的温度范围内对新疆铬铁矿进行了穆斯堡尔谱研究。根据低温谱形,将全谱分解成三套双峰,其中第Ⅰ、Ⅱ套是四面体中的 Fe^(2+)产生的。第Ⅲ套是八面体中的Fe^(3+)产生的,这几套谱的同贡异能移及其与温度的关系证实了这种分解的正确性,从电四极分裂与温度的关系确定四面体中 Fe^(2+)离子能级因 Jahn-Teller 效应而分裂的宽度相应为212和179cm^(-1)。对于此种铬铁矿三价铁与二价铁的含量比为 Fe^(3+)/Fe^(2+)=0.35±0.03。本工作有力地支持了 Fe^(2+)处于四面体和 Fe^(3+)处八面体的有序分布模型。
Mossbaner spectra of a natural chromite fron Xin Jiang deposit has been reorded at a wide temperature range between 20K and 750K.Based on the low temperature mossbauer patterns,all the spectra are fitted by three doublets: the two are attributed to the tetredral(A)site Fe^(2+),the third to the oc- tahedral(B)site Fe^(3+).Such assignment was confirmed by detailed analysis of the temperature dependent center shifts and other parameters.The Mossbauer ratio Fe^(2+)/Fe^(3+)was determineted to be 0.35+0.03.T dependent quadrupole splittings of two doublets are interpreted in terms of John-Teller distortion which lifts the degeneracy of the Eg level by 212 and I79 cm^(-1)respectively. Thus our results strong support the ordered distribution with Fe^(2+)in A site and Fe^(3+)in B site.
出处
《武汉大学学报（自然科学版）》
CSCD
1991年第4期29-34,共6页
Journal of Wuhan University(Natural Science Edition)
关键词
铬铁矿
穆斯堡尔谱
次近邻效应
mossbauer effect
chromite
next-nearest
neighbour effect
