Magnetic effects on structural, elastic and surface properties of the 3d ferromagnets

Abstract

Assuming saturated ferromagnetism, the anomalous crystal structures of the magnetic 3d transition Fe, Co and Ni can be explained from simple band filling arguments. The exceptional elastic properties of Fe and Co are well described by full potential linear muffin-tin orbital (FP-LMTO) electronic structure calculations using the local density approximation for the electron density functional. Analysis shows that the behaviour of the tetragonal shear constant C′ can be understood from the contribution of the partially filled spin down band, whereas the electrons in the almost filled spin up band only play a minor role. This strong reduction in the number of electrons which contribute to the elastic properties explains the anomalous behaviour. The surface magnetism of the 3d metals was studied by means of a Green's function technique within the tight-binding linear muffin-tin orbital (TB-LMTO) method. It was found that the anomalous surface energies of the 3d transition metals can be explained in terms of itinerant surface magnetism. For some of the magnetic metals an unusual property is found, namely that the lowest surface energy is not connected to the most densely packed surface.