title: Tuning the colloidal crystal structure of magnetic particles by external field.
abstract: Manipulation of the self-assembly of magnetic colloidal particles by an externally applied magnetic field paves a way toward developing novel stimuli responsive photonic structures. Using microradian X-ray scattering technique we have investigated the different crystal structures exhibited by self-assembly of core-shell magnetite/silica nanoparticles. An external magnetic field was employed to tune the colloidal crystallization. We find that the equilibrium structure in absence of the field is random hexagonal close-packed (RHCP) one. External field drives the self-assembly toward a body-centered tetragonal (BCT) structure. Our findings are in good agreement with simulation results on the assembly of these particles.
authors.affiliation: Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for NanoMaterials Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht (The Netherlands).
authors.forename: Antara
authors.initials: A
authors.lastname: Pal
authors.forename: Vikash
authors.initials: V
authors.lastname: Malik
authors.forename: Le
authors.initials: L
authors.lastname: He
authors.forename: Ben H
authors.initials: BH
authors.lastname: Erné
authors.forename: Yadong
authors.initials: Y
authors.lastname: Yin
authors.forename: Willem K
authors.initials: WK
authors.lastname: Kegel
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Petukhov
keywords: X-ray scattering; colloidal crystals; core-shell nanoparticles; magnetic field; self-assembly