Crystal structure and optical properties of oxynitride rare-earth tantalates RTa-(O, N) (R = Nd, Gd, Y) - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Materials Research Bulletin Année : 2008

Crystal structure and optical properties of oxynitride rare-earth tantalates RTa-(O, N) (R = Nd, Gd, Y)

Résumé

X-ray absorption and photoluminescence were used to investigate the structure of rare-earth tantalum oxynitrides RTa-(O, N) (R = Nd, Gd, Y). Owing to the size of the rare-earth element, the crystal structure tends towards the pyrochlore or defect fluorite-type structure. EXAFS suggested neodymium and yttrium atoms are coordinated either by 6 + 2 or 6 oxygen/nitrogen atoms in the Nd or Y respective oxynitrides although the coordination number of tantalum is six in both compounds. Photoluminescence for 5 at.% doped europium showed the spectra compatible with the point symmetry C3v lower than Oh in fluorite and D3d in pyrochlore structure type for both the Gd and Y tantalum oxynitrides. These measurements supported that their structure types were basically pyrochlore for Nd and Gd tantalum oxynitrides and defect fluorite for Y tantalum oxynitride but they are highly defective.

Domaines

Matériaux

Dates et versions

hal-00373297 , version 1 (03-04-2009)

Identifiants

Citer

Shinichi Kikkawa, Takashi Takeda, Akira Yoshiasa, Pascal Maillard, Franck Tessier. Crystal structure and optical properties of oxynitride rare-earth tantalates RTa-(O, N) (R = Nd, Gd, Y). Materials Research Bulletin, 2008, 43 (4), pp.811-818. ⟨10.1016/j.materresbull.2007.06.036⟩. ⟨hal-00373297⟩
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