Electronic structure and magnetic properties of KCrSe

KCrSe characterized by x-ray powder diffraction is a layered compound isostructural with NaCrSe: a = 3.80 Å; c = 22.19 Å; space group R3m, The magnetic properties are similar to those of NaCrSe but with an even more pronounced difference between the intralayer and interlayer exchange interactions of Cr 3d localized moments. The magnetic susceptibility above 100 K is of a Curie-Weiss nature; the Curie temperature is +250 K. An antiferromagnetic transition with T = 40 K occurs; in the ordered state, ferromagnetic layers are coupled antiferromagnetically. The analysis showed the intralayer exchange interaction J/k and interlayer exchange interaction J/k to be 16.7 K and -0.06 K, respectively. A band-structure calculation using the LSW method was performed for KCrSe in the ferromagnetic state (neglecting the interlayer antiferromagnetic ordering). The calculations show that KCrSe is a semiconductor with a band gap of 0.7 eV. The potassium atoms are nearly ionized. The Cr 3d(t) states are completely spin polarized. The electronic configuration of Cr is (3d), with a local magnetic moment of 3μB per Cr atom.