Spin-Spin Interactions in the Oxides A_3M'MO6(M-Rh,Ir A=Ca, Sr; M'=Alkaline Earth, Zn, Cd, Na) of the K_4CdCI_6 Structure Type Examined by Electronic Structure Calculations

다국어 초록 (Multilingual Abstract)

The oxides A_3M'MO_6 (M=Rh, Ir, A=Ca, Sr, M'=alkaline earth, Zn, Cd) of the K_4CdCl_6 structure type consist of isolated(MO_6)^8- octahedral anions and exhibit an antiferromagnetic ordering at low temperatures. The spin-spin interactions in these oxides, Ca_3NaMO_6(M=Ir, Ru), and Sr_3NaRuO_6 were examined by calculating how strongly the t_2g-block levels of adjacent(MO_6)^(6+n)- (n=1,2) anions interact in the presence and absence of the intervening cations A^2+ and M'^n+ (n=1,2). Our calculations show that the spin-spin interactions in these oxides are three-dimensional, and the superexchange interactions occur mainly through the short intrachain and interchain M-O…O-M linkages. When the M^n+ cation is very small compared with the A^2+ cation, the intrachain interaction is substantially stronger than the interchain interaction. The opposite is found when the sizes of the M^n+ and A^2+ cations become similar.

목차 (Table of Contents)

• 요약
• 1.Introduction
• 2.Dimer Model for Spin-Spin Interactions
• 3.Dalculations
• 4.Treds in the Spin-Spin Interactions
• 5.Discussion
• 6.Concluding Remarks