Semimagnetic Lead Salt Alloys

Abstract

AbstractThe magnetic and electronic properties of pseudobinary alloys of the lead compounds (PbTe,PbSe)with Manganese, Europium and Gadolinium are reviewed. These materials have a direct minimum gap at the L-point of the Brillouin zone. The addition of Mn, Eu, or Gd to the diamagnetic hosts causes a rather weak antiferromagnetic exchange interaction. For sufficiently high carrier concentrations (10 2 0 -102 1 cm−3) a ferromagnetic interaction occurs due to RKKY interaction. The spin-spin exchange interaction between the Bloch states and the localized 3d or 4f states is characterized by rather small exchange integrals and the limited applicability of the mean field approximation for the description of energy band parameters like g-factors. Interband transitions in PbMnTe and PbMnS lend support to a zeromagnetic field splitting (“spin-splitting”)of band states which increases linearly with Mn-content up to several meV at temperatures below 4K.