ELECTRONIC-STRUCTURE AND MAGNETISM OF KMF(3) (M=MN,FE,CO,NI)

Antiferromagnetic electronic-structure calculations of the perovskite fluorides KMF(3) (M=Mn,Fe,Co,Ni) carried out using the linear muffin-tin orbital method are reported here. The calculations have successfully predicted the insulating gaps of the systems KMnF3 and KNiF3. However, in the cases of KFeF3 and KCoF3 the insulating gap could not be accounted for by these calculations and this is found to be due to the fact that the spin-density-functional theory is inadequate to show the splitting of the Mt(2g) bands. However, the magnetic moments obtained from the calculations are comparable to the experimental values, and also the calculated density of states show good agreement overall with the photoemission data.