Pressure and chemical substitution effects in the local atomic structure of BaFe2As2

• Autor(a) principal: Granado, E.
• Data de Publicação: 2011
• Outros Autores: Ferreira, Leticie Mendonca, Garcia, Flávio, Azevedo, Gustavo de Medeiros, Fabbris, Gilberto Fernandes Lopes, Bittar, Eduardo Matzenbacher, Adriano, C., Garitezi, T. M., Rosa, P. F. S., Bufaiçal, L. F., Avila, M. A., Terashita, H., Pagliuso, P. G.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/104526
• topic: Física da matéria condensada; Momentos magnéticos; Diagramas de fase; Estrutura fina estendida de absorção de raios x (EXAFS); Compostos de ferro; Compostos de bário; Compostos de cobalto; Compostos de potássio

The effects of K and Co substitutions and quasihydrostatic applied pressure (P < 9 GPa) in the local atomic structure of BaFe2As2, Ba(Fe0.937Co0.063)2As2 and Ba0.85K0.15Fe2As2 superconductors were investigated by extended x-ray absorption fine structure (EXAFS) measurements in the As K absorption edge. The As-Fe bond length is found to be slightly reduced ( >~0.01 Å) by both Co and K substitutions, without any observable increment in the corresponding Debye-Waller factor. Also, this bond is shown to be compressible [κ = 3.3(3) × 10−3 GPa−1]. The observed contractions of As-Fe bond under pressure and chemical substitutions are likely related with a reduction of the local Fe magnetic moments, and should be an important tuning parameter in the phase diagrams of the Fe-based superconductors.