Structural Disorder and Classical Spin-Glass Behaviour in Ba3Fe2SbO9

Abstract

A new 6H-type perovskite Ba 3 Fe 2 SbO 9 has been synthesised for the first time. Synchrotron and neutron powder diffraction data reveal complete structural disorder between Sb and Fe in the octahedral perovskite B sites. This results in classical spin-glass behaviour, which we characterise using magnetic susceptibility, magnetisation, and heat capacity measurements, although some evidence is seen for a transition to a partially ordered spin-glass like state below 24 K. The behaviour of Ba 3 Fe 2 SbO 9 is compared with that of the 6H-type perovskite Ba 3 Fe 2 WO 9 , which displays antiferromagnetic character below T N ¼ 290 K before entering a glassy state below T f ¼ 60 K. Differences between the magnetism in these two phases are discussed in terms of the complete structural disorder between the Fe and Sb ions in the former case, versus partial disorder (limited to the distribution and local orientation of Fe-W and Fe-Fe dimer units) in the latter.

An Introduction to Molecular Magnetism: SANZMAG-1 (Southampton-Australia-New Zealand Workshop on Molecular Magnetism)

“…[1,2] The issue also contains several Focus and Research articles detailing the magnetic properties of novel molecular complexes, clusters, coordination polymers and solid state materials. [3][4][5][6][7][8][9][10][11][12] We would like to thank all of the organisers and participants in this inaugural SANZMAG conference which allowed for its success and we look forward to the next instalment. We also sincerely thank all of the authors who have made such an effort to contribute to this issue.…”