Eur. Phys. J. B 78, 411-415 (2010)
https://doi.org/10.1140/epjb/e2010-10522-1

High-pressure neutron diffraction study of BaFe₂As₂

¹ Department of Chemistry, University of Aarhus, 8000 Aarhus C, Denmark
² Institute Max von Laue-Paul Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France

Corresponding author: ^a jenserik@chem.au.dk

Received: 6 July 2010
Revised: 15 October 2010
Published online: 29 November 2010

Abstract

The crystal structure of BaFe₂As₂ was studied by high-pressure neutron powder diffraction in the pressure range from ambient to 6.5 GPa as well as in the temperature range from 12 K to 293 K at 4.4 GPa and no pressure or temperature induced phase changes were observed. The compression mechanism of BaFe₂As₂ was found to be anisotropic as the a- and c-axes are reduced by 2.49 and 3.66%, respectively at 6.5 GPa. Within the FeAs layers the Fe-As and Fe-Fe bonds decrease by 2.49 and 3.66%, respectively. The Ba-As distance decreases by 3.70% while the As-As inter-atomic distance along the c-axis exhibits a complex pressure dependence. The bulk modulus B₀ and its pressure derivative B₀' were determined to be B₀ = 59(2) GPa and B₀' = 6.1(7) at ambient temperature.