Structure determination and crystal chemistry of large repeat mixed-layer hexaferrites

IUCrJ

Delacotte, C.¹  Whitehead, G.F.S.²  Pitcher, M.J.³ 

[1]Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK

[2]Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK

[3]Diamond Light Source, Harwell Campus, Chilton, Oxon OX11 0DE, UK

关键词: LARGE REPEAT HEXAFERRITES;    MIXED-LAYER STRUCTURAL MODELS;    POLYTYPES;    STACKING SEQUENCES;    DEFECTS;    MAGNETIC PROPERTIES;   

DOI  :  10.1107/S2052252518011351

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

Hexaferrites are an important class of magnetic oxides with applications in data storage and electronics. Their crystal structures are highly modular, consisting of Fe- or Ba-rich close-packed blocks that can be stacked in different sequences to form a multitude of unique structures, producing large anisotropic unit cells with lattice parameters typically >100 Å along the stacking axis. This has limited atomic-resolution structure solutions to relatively simple examples such as Ba2Zn2Fe12O22, whilst longer stacking sequences have been modelled only in terms of block sequences, with no refinement of individual atomic coordinates or occupancies. This paper describes the growth of a series of complex hexaferrite crystals, their atomic-level structure solution by high-resolution synchrotron X-ray diffraction, electron diffraction and imaging methods, and their physical characterization by magnetometry. The structures include a new hexaferrite stacking sequence, with the longest lattice parameter of any hexaferrite with a fully determined structure.

【 授权许可】

CC BY