Preparation and Properties of Rare-Earth Compounds
Semi-annual technical rept. 4 Jun-4 Dec 1970
BATTELLE MEMORIAL INST COLUMBUS OH COLUMBUS LABS
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Research was performed to investigate potentially useful properties of rare-earth materials, including studies in the areas of magnetoferroelectricity, narrow-band and narrow-gap compounds, rare-earth pnictides, and cooperative fluorescence of rare-earth ions in crystals. Manganates of Dy, Y, Ho, and Yb including high-pressure orthorhombic phases of the last three and molybdates of Eu, Gd, and Tb have been prepared and their electrical and magnetic properties studied. Electron paramagnetic resonance studies of the gradual low-temperature semiconductor-to-metal transition in SmB6 show a resonance which tentatively has been attributed to an excited state of Sm2. Though recently reported research indicates that all rare-earth monopnictides REPn Pn N, P, As, Sb, or Bi with NaCl structure are metallic, this may be due to intrinsic non-stoichiometry, and the question of whether the nitrides. Samples of GdN have been prepared and nuclear magnetic resonance studies will be used to determine the role of defects and to try to elucidate the electronic character. Finally, studies on the two-photon infrared-excited red fluorescence of Ho3 ions in CaF2 have established that the fluorescence arises from cooperative energy transfer between Ho3 ions rather than from successive excitation of a single ion. Work is continuing to determine the exact mechanism of the cooperative process.
- Electricity and Magnetism
- Solid State Physics