Magnetic behavior of diluted lanthanoid-pnictide systems.

We describe a new class of low-carrier-density magnetic materials based on lanthanide-substituted scandium and yttrium pnictides. In general, these III-V compounds have energy gaps in the vicinity of 1 eV, and like most of the lanthanide pnictides, form in the Bl(rocksalt) structure. Substitution of rare earths for Y or Sc to form solid solutions is readily achieved. For example, we have produced Gd sub x Y sub (1-x) N by reactive magnetron cosputtering, and obtained epitaxial growth on sapphire substrates resulting in high-quality single-crystal thin films. These films exhibit moderately low carrier densities and high mobilities, and exhibit magnetization loops with hysteresis, a finite remanence, and apparent saturation in fields of about 10kOe, yet which cannot be described as simple ferromagnets. In this paper we present a preliminary look at some of the properties of these materials.