Magnetic exchange interactions and phase transition in Fe/V(100), V/Fe/V(100) and Fe/V/Fe/V(100) films.

We present the magnetic properties of bcc Fe films on and embedded in bcc-V(100) substrates in their paramagnetic phase above the Curie temperature. We have used a first-principles electronic structure method based on the spin-density functional theory and the spin fluctuations in the paramagnetic phase are described using the disordered local moments model. We have calculated the local magnetic moments, magnetic correlations and the Curie temperature of several Fe/V(100) and V/Fe/V(100) systems. In general, the Fe layers in close proximity to V have their magnetic moments suppressed, while in the interior of the film, the value of the magnetic moment oscillates from one layer to the other. When the films are capped by a V layer, the magnitudes of the magnetic moments decreases. The Curie temperature also shows an interesting oscullatory behaviour as the V capping layer thickness is increased. In the Fe/V/Fe/V(100) films, we observed that the exchange interactions between the two Fe layers across the spacer exhibits an oscillating behaviour. [ABSTRACT FROM AUTHOR]