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Title: Tuning the structure and habit of iron oxide mesocrystals

A precise control over the meso- and microstructure of ordered and aligned nanoparticle assemblies, i.e., mesocrystals, is essential in the quest for exploiting the collective material properties for potential applications. In this work, we produced evaporation-induced self-assembled mesocrystals with different mesostructures and crystal habits based on iron oxide nanocubes by varying the nanocube size and shape and by applying magnetic fields. A full 3D characterization of the mesocrystals was performed using image analysis, high-resolution scanning electron microscopy and Grazing Incidence Small Angle X-ray Scattering (GISAXS). This enabled the structural determination of e.g. multi-domain mesocrystals with complex crystal habits and the quantification of interparticle distances with sub-nm precision. Mesocrystals of small nanocubes (l = 8.6 12.6 nm) are isostructural with a body centred tetragonal (bct ) lattice whereas assemblies of the largest nanocubes in this study (l = 13.6 nm) additionally form a simple cubic (sc) lattice. The mesocrystal habit can be tuned from a square, hexagonal to star-like and pillar shapes depending on the particle size and shape and the strength of the applied magnetic field. Finally, we outline a qualitative phase diagram of the evaporation-induced self-assembled superparamagnetic iron oxide nanocube mesocrystals based on nanocube edge length and magnetic fieldmore » strength.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [2] ;  [6] ;  [6]
  1. Stockholm Univ. (Sweden). Dept. of Materials and Environmental Chemistry; Uppsala Univ. (Sweden). Angstrom Lab., Dept. of Engineering Sciences
  2. Forschungszentrum Julich (Germany). Juelich Centre for Neutron Science (JCNS), Peter Grunberg Inst. PGI, JARA-FIT
  3. Univ. zu Koln (Germany). Dept. of Chemistry
  4. Forschungszentrum Julich (Germany). Juelich Centre for Neutron Science (JCNS), Peter Grunberg Inst. PGI, JARA-FIT; Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Ion Beam Physics and Materials Research
  5. Forschungszentrum Julich (Germany). Juelich Centre for Neutron Science (JCNS), Peter Grunberg Inst. PGI, JARA-FIT; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  6. Stockholm Univ. (Sweden). Dept. of Materials and Environmental Chemistry
Publication Date:
OSTI Identifier:
1319205
Grant/Contract Number:
AC05-00OR22725; FP7- NMP-604448; PIEF-GA-2011- 298918; DI 1788/2-1
Type:
Accepted Manuscript
Journal Name:
Nanoscale
Additional Journal Information:
Journal Volume: 8; Journal Issue: 34; Journal ID: ISSN 2040-3364
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY