Spin-spin interactions of Ce3+ ions in the elpasolite crystal Cs2NaInCl6

The EPR method is used to study at T=4.2 K crystals of Cs₂NaInCl₆:Ce³⁺ (1 mol %) at which have elpasolite structure. A solitary cubic Ce³⁺ center and three types of Ce³⁺-Ce³⁺ pairs were observed, for which the spin-spin interaction parameters D and E were determined. It is established that deformation of the local structure results in a shift {Δg} of the pair relative to the g-factor of the solitary center. Models of the solitary center and the three types of Ce³⁺-Ce³⁺ pairs are discussed, as well as the nature of the spin-spin interactions in the pairs. The non-dipole nature of the interactions is established. Possible chains for the creation of an indirect exchange between the Ce³⁺ ions are considered. Fiz. Tverd. Tela (St. Petersburg) 39, 62–67 (July 1997)