Fig. 2.

Magnetic field-induced self-assembly of oriented superlattices from maghemite nanocubes. (A) TEM image of magnetic-field-induced self-assembly of maghemite nanocubes into an oriented superlattice. (Scale bar: 100 nm.) (B) Schematic presentation of the magnetic-field-induced self-assembly procedure. A single permanent magnet was first moved slowly from point 1 to point 2 and then moved in the orthogonal direction immediately (within 2 min) after one or several drops of the nanocube dispersion was placed onto the TEM grid. (C) A schematic representation of a simple cubic superlattice formed by magnetic-field-induced self-assembly. (D and E) Atomic (D) and mesoscale (E) electron diffraction patterns obtained from A. (F) TEM image obtained from the edge of the superlattice in A. (Scale bar: 100 nm.)