Lattice dynamics of xenotime: The phonon dispersion relations and density of states of LuPO{sub 4}
- Argonne National Laboratory, Argonne, Illinois 60439-4814 (United States)
- Technische Universitaet Dresden, Dresden (Germany)
- Forschungszentrum Karlsruhe, INFP, D-76021, Karlsruhe (Germany)
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056 (United States)
LuPO{sub 4} is the nonmagnetic end member of a series of rare-earth phosphates with a common zircon-type crystal structure. The phonon-dispersion curves of LuPO{sub 4} along the [x,0,0], [x,x,0], and [0,0,x] symmetry directions were measured by neutron triple-axis spectroscopy using single-crystal samples. The phonon density of states was determined by time-of-flight neutron scattering using polycrystalline samples. Phonons involving mainly motions of rare-earth ions were found to be well separated in energy from those of the P and O vibrations. A large gap in the phonon-frequency-distribution function, which divides the O-P-O bending-type motions from the P-O stretches, was observed. All of the experimental results were satisfactorily accounted for by lattice-dynamic shell-model calculations. LuPO{sub 4} is a host material for the incorporation of rare-earth ions to produce activated luminescence. Information regarding the phonon and thermodynamic properties of LuPO{sub 4} is pertinent to extended investigations of additional rare-earth spin-lattice interactions in other zircon-structure rare-earth orthophosphates. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 544932
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 18; Other Information: PBD: Nov 1997
- Country of Publication:
- United States
- Language:
- English
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