Article pubs.acs.org/cm
B‑Cation Order Control of Magnetism in the 1322 Perovskite CaCu3Fe2Nb2O12 Mark S. Senn,†,⊥ Wei-tin Chen,‡,# Takashi Saito,‡ Susana García-Martín,§ J. Paul Attfield,† and Yuichi Shimakawa*,‡,∥ †
Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom ‡ Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan § Departamento de Química Inorgánica, Facultad de C.C. Químicas, Universidad Complutense, Madrid-28040, Spain ∥ Japan Science and Technology Agency, CREST, Uji, Kyoto 611-0011, Japan ABSTRACT: Cation ordering in the 1322 perovskite CaCu3Fe2Nb2O12 has been investigated by synchrotron X-ray diffraction structure analysis, high-resolution electron microscopy, and magnetic measurements. All of the samples have full 1:3 ordering of Ca and Cu cations at the perovskite A-sites, but the Fe and Nb cations at the B sites show different degrees of ordering depending on the synthesis conditions. A slow-cooled sample has almost complete rock-salt-type 1:1 cation ordering at the B sites, but a rapidly cooled sample has no long-range Bcation arrangement. The ordered compound shows a large saturated magnetization (5.7 μB/formula unit (fu)) below 170 K due to the ferrimagnetism of the A′-site Cu2+ and B-site Fe3+ spins, whereas the B-site disordered form has a small magnetization (
