Sr 1/2 Ce 5/14 □ 1/7 WO 4 : a new modulated ternary scheelite compound

Rafael Hernandez Damascena dos Passos (1, 2) , Madjid Arab (1) , Carlson Pereira de Souza (2) , Christine Leroux (1)

1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
2 UFRN - Universidade Federal do Rio Grande do Norte [Natal]

For the first time, a ternary tetragonal scheelite structure tungstate with strontium and cerium cations,(Sr,Ce)WO4, was synthesized. As much as 35 % Ce could be inserted in the structure, leaving 1/7 of the (Sr,Ce) cation sites vacant. Partial ordering of Sr and Ce, with atomic displacements, were evidenced by high resolution electron microscopy. 2D incommensurate modulations occur in this material, in small domains 20 nm in size. The band gap of this compound is significantly lower than the band gap of SrWO4 and this was related to the distortions of WO4 and (Sr,Ce)O8 polyhedra. The bang gap value of 3.2 eV makes Sr1/2Ce5/14□1/7WO4 a promising candidate for violet luminescence.

Mots clés: scheelite; ordering; vacancies; incommensurate; high resolution electron microscopy; simulations; x ray diffraction; band gap.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Cristallographie

Rafael Hernandez Damascena dos Passos, Madjid Arab, Carlson Pereira de Souza, Christine Leroux. Sr 1/2 Ce 5/14 □ 1/7 WO 4 : a new modulated ternary scheelite compound. Acta Crystallographica Section B, 2017, B73 (3), pp.466-473. ⟨10.1107/S2052520617002827⟩. ⟨hal-01541637⟩