Li—Zn铁氧体单晶的分子场系数

Determination of Molecular Field Coefficients in Li-Zn Ferrite Single Crystals

本文报导用助熔剂法生长出如下成分的铁氧体单晶:(Fe_(1-z)Zn_z)_A[Li_(0.5-(Z/2)) Fe_(1.5+(Z/2))]_BO_4,在有变温装置的磁天平上,从液氮温度至居里温度范围内测量出不同锌含量的Li—Zn铁氧体单晶的Ms—T曲线。按Néel亚铁磁分子场理论,以逐次逼近法通过反复叠代计算,确定出Li—Zn铁氧体单晶的分子场系数与锌含量间有如下线性关系 N_(AA)=-146(1+0.384Z) N_(BB)=-58.3(1-0.356Z) N_(AB)=265(1-0.151Z) (moles/cm^3)为确定上述结果的适用性,对不同锌含量的锂锌铁氧体计算了磁矩—温度曲线,并与实验值进行比较,结果表明,理论与实验基本符合。这就可为在一个较宽的含锌量范围内提供予言Li—Zn铁氧体性能的基本数据。

The Li-Zn ferrite single crystals have been grown by the flux-melt method, and the Ms vs.T curves were measured for single cystals, in which the composition of Zn is up to 0.50 atoms per formula unit, and the temperature range is from 77K to Tc.By fitting the Neel theory of ferrimagnetism to Ms vs. T data for several single crystals of the ferrite( Fe1-zZnz) [Li0.5-z/2Fe1.5+z/2]O4,the molecular field coefficients were determined to have the following linear relationship with the amount of Zn substitution (for Z≤0.5)Naa=-146 (1+0.384Z)Nbb=-58.3 (1-0.356Z)Nab=265(1-0.151Z) moles/cm3With the above relations curves of Ms vs. T have been computed or the Zn substituded Li-ferrite, and the results show a good agreement between theory and experiment.