Influence of the Band Occupation on the Electronic Damping in the s‐f Model

Abstract

The fundamental element in the theory of the so-called s-f model which i s widely accepted as a good description of magnetic 4f-or 5f-systems i s the exchange coupling (s-f coupling) between the conduction band electrons and the lattice of localized magnetic moments. The s-f coupling influences optical, electrical, and magnetic properties of these materials. A s first pointed out by Shastry and Mattis /1/ the physical properties depend very strongly on the sign of the s-f exchange. In the Eu chalcogenides a s well as in Cd theelectron spin couples ferromagnetically (FM) to the f spin /2/, whereas i n the actinide compounds such a s the uranium chalcogenides the s-f coupling seems to be antiferromagnetic (AFM) /3 to 5/.The temperature and carrier concentration dependence of the conduction electron spin polarization for 4f-and 5f-compounds was discussed by many authors /6 to 8/. Nolting and Ole8 /9/ determined the n-dependence of the Curie temperature TC of Gd-doped EuO and E S . Woolsey and White /lo/ calculated the electron and magnon lifetime as function of the doping in the lowtemperature spin-wave approximation for FM s-f exchange.In fact the imaginary parts of the energies corresponding to lifetime broadening effects a r e not considered till now. In our previous papers /11, 12/ (hereafter referred to a s I and II) using a Green function methoa proposed by Tserkovnikov /13/ w e have extended the theory to higher order, and calculated for the first time beyond the RPA t h e electronic spectrum and the damping of

Comparison of the Multiferroic Properties of Ion‐Doped Hexagonal LuFeO3 and LaFeO3

“…The electronic energies were calculated using the s–d model [ 24 ] from the Green's functions …”

Spin wave damping anisotropy in ferromagnetic EuO

“…The theoretical results were applied to CdCr2Se4. The band occupation dependence of the conduction electron magnetisation of the energy gap and of the electronic damping for I > 0 and I < 0 was obtained in [15].…”