Calculation of Magnetic and Electric Hyperfine Fields in Metals

Abstract

This article is divided into two parts. The first part deals with the theory of the origin of hyperfine fields in ferromagnetic iron and cobalt, while the second part deals with the theory of nuclear quadrupole interaction in pure non-cubic metals. In the first part, dealing with hyperfine fields in ferromagnets, the various mechanisms that can produce the hyperfine field are reviewed and their contributions, as obtained from calculated band wave-functions are analysed. Comparison is made with experiment and the possible improvements needed in the electric theory are discussed. In the second part of the article, the electronic field-gradients in a number of hcp metals are discussed. The ionic and electron contributions are analysed and comparison is made with experimental data with respect to both magnitude and sign of the quadrupole coupling constants where available. The nature of the accuracy to be expected from the use of wave-functions obtained by actual potentials and pseudo-potentials is discussed. The implications of theoretical results in the pure metals for nuclear quadrupole interaction in alloys is discussed. In the alloys, a substantial amount of experimental data is available currently by the perturbed angular correlation and other techniques.