Electronic structure and magnetic properties of KCrSe2

KCrSe2 characterized by x-ray powder diffraction is a layered compound isostructural with NaCrSe2: a = 3.80 Å; c = 22.19 Å; space group R_3m. The magnetic properties are similar to those of NaCrSe2 but with an even more pronounced difference between the intralayer and interlayer exchange interactions of Cr3+ 3d3 localized moments. The magnetic susceptibility above 100 K is of a Curie–Weiss nature; the Curie temperature is +250 K. An antiferromagnetic transition with TN = 40 K occurs; in the ordered state, ferromagnetic layers are coupled antiferromagnetically. The analysis showed the intralayer exchange interaction J1/k and interlayer exchange interaction J2/k to be 16.7 K and −0.06 K, respectively. A band-structure calculation using the LSW method was performed for KCrSe2 in the ferromagnetic state (neglecting the interlayer antiferromagnetic ordering). The calculations show that KCrSe2 is a semiconductor with a band gap of 0.7 eV. The potassium atoms are nearly ionized. The Cr 3d(t2g) states are completely spin polarized. The electronic configuration of Cr is (3d)3, with a local magnetic moment of 3μB per Cr atom.