Local spin density investigations in oxide systems with half metallic ferromagnetic properties

The electronic and magnetic properties of two oxides systems: CrO2 and CaMn O2.5; the latter being a naturally doped manganite are examined within the density functional theory. The respective magnetizations of 2 and 4 mu (B), in agreement with Hund's first rule, show evidence of a half-ferromagnetic behavior for these systems exhibiting a metallic behavior for the majority spins and a semi-conducting one for the minority spins. The chemical bondi ng is shown to be spin dependent with majority electron spins playing a det ermining role. (C) 2000 Elsevier Science Ltd. All rights reserved.