Huge magneto-optical effects in half-metallic double perovskites -: art. no. 184414

Using generalized-gradient-corrected full-potential density-functional calculations we have studied the magneto-optical properties of double perovskites A(2)BB(')O(6), A=Ca, Sr, and Ba; B=Fe; and B-'=Mo, W, and Re. Sr2FeWO6 has the maximum polar Kerr rotation of 3.87degrees and specific Faraday rotation of 4.5x10(5) deg cm(-1). All other compounds have Kerr rotation more than 1degrees, except Ca2FeMoO6 which has maximum Kerr rotation of 0.5degrees. Our electronic structure studies show that all these compounds are half-metallic in the ferromagnetic configuration. The large Kerr rotation is found to be due to the combined effects of relatively large exchange splitting from Fe, large spin-orbit coupling due to 4d or 5d elements, large offdiagonal conductivity, and half-metallicity.