Exchange Interaction and Cubic Crystal Field Splitting Parameter of Fe^<3+> in Spinel Structure

概要

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The line widths of paramagnetic resonance absorption of Fe^<3+> ions in MgAl_2O_4 and ZnAl_2O_4 polycrystals and of Mn^<2+> ions in ZnAl_2O_4, having the same spinel crystal structure as ferrite, are measured as a function of concentration. The cubic crystal field splitting parameters α of Fe^<3+> ion at A- and B-sites are determined from the line widths extrapolated to zero concentration: α_A = 1.0 × 10^<-2>cm^<-1> and α_B = 3.1 × 10^<-2>cm^<-1>. α_B/α_A = 3.1. On the other hand, the magnitudes of exchange integral between Fe^<3+> ions in A- and B-sites or in B- and B-sites are estimated from the decrease of line width due to exchange narrowing as the concentration increases, namely, J_<AB>/gβ = 1.32 × 10^5 Oe and J_<BB>/gβ = 1.90 × 10^3Oe. The Curie temperatures obtained from the exchange integral are in agreement with the Curie temperatures of Mg-ferrite and Zn-ferrite measured experimentally.
社団法人日本物理学会の論文
1960-07-05