Anisotropic dynamics of magnetic colloidal cubes studied by X-ray photon correlation spectroscopy
Pal, Antara LU ; Kamal, Md Arif LU ; Zinn, Thomas ; Dhont, Jan K.G. LU and Schurtenberger, Peter LU
(2021)
In Physical Review Materials
5(3).
- Abstract
Herein we present our results on the investigation of the influence of external magnetic fields on the anisotropic collective dynamics of core/shell colloidal cubes having a hematite core and silica shell. Owing to the hematite cores, these micrometer-sized particles possess permanent dipole moments, which are at an angle with respect to the long diagonal of the cubes. As a result, they self-assemble into chains, which subsequently sediment to form higher-order structures. Using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy, the anisotropic dynamics within these structures at the nearest-neighbor length scale was probed. The relaxation of the intermediate scattering function follows a compressed exponential... (More)
Herein we present our results on the investigation of the influence of external magnetic fields on the anisotropic collective dynamics of core/shell colloidal cubes having a hematite core and silica shell. Owing to the hematite cores, these micrometer-sized particles possess permanent dipole moments, which are at an angle with respect to the long diagonal of the cubes. As a result, they self-assemble into chains, which subsequently sediment to form higher-order structures. Using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy, the anisotropic dynamics within these structures at the nearest-neighbor length scale was probed. The relaxation of the intermediate scattering function follows a compressed exponential behavior along all the different directions with respect to the external field-parallel, perpendicular, and at an angle ≈45a-indicating hyperdiffusive behavior. We believe that the inhomogeneous distribution of stress points originating from the interplay of external field-induced (both gravitational and magnetic) alignment of the chains are responsible for the anomalous dynamics. The effective diffusion coefficients along and at ≈45a angle exhibit mild de Gennes narrowing, which is not very common for hyperdiffusive dynamics. We rationalize our observations by considering a superposition of diffusive and stress-induced ballistic processes and argue that depending on the azimuthal direction the relative contribution from these two processes changes.
(Less)
- author
- Pal, Antara
LU
; Kamal, Md Arif
LU
; Zinn, Thomas
; Dhont, Jan K.G.
LU
and Schurtenberger, Peter
LU
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review Materials
- volume
- 5
- issue
- 3
- article number
- 035603
- publisher
- American Physical Society
- external identifiers
-
- scopus:85104334912
- ISSN
- 2475-9953
- DOI
- 10.1103/PhysRevMaterials.5.035603
- language
- English
- LU publication?
- yes
- id
- 1663601a-986f-4599-8d5f-d6b562111c98
- date added to LUP
- 2021-04-26 14:02:35
- date last changed
- 2023-11-08 13:26:47
@article{1663601a-986f-4599-8d5f-d6b562111c98,
abstract = {{<p>Herein we present our results on the investigation of the influence of external magnetic fields on the anisotropic collective dynamics of core/shell colloidal cubes having a hematite core and silica shell. Owing to the hematite cores, these micrometer-sized particles possess permanent dipole moments, which are at an angle with respect to the long diagonal of the cubes. As a result, they self-assemble into chains, which subsequently sediment to form higher-order structures. Using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy, the anisotropic dynamics within these structures at the nearest-neighbor length scale was probed. The relaxation of the intermediate scattering function follows a compressed exponential behavior along all the different directions with respect to the external field-parallel, perpendicular, and at an angle ≈45a-indicating hyperdiffusive behavior. We believe that the inhomogeneous distribution of stress points originating from the interplay of external field-induced (both gravitational and magnetic) alignment of the chains are responsible for the anomalous dynamics. The effective diffusion coefficients along and at ≈45a angle exhibit mild de Gennes narrowing, which is not very common for hyperdiffusive dynamics. We rationalize our observations by considering a superposition of diffusive and stress-induced ballistic processes and argue that depending on the azimuthal direction the relative contribution from these two processes changes.</p>}},
author = {{Pal, Antara and Kamal, Md Arif and Zinn, Thomas and Dhont, Jan K.G. and Schurtenberger, Peter}},
issn = {{2475-9953}},
language = {{eng}},
number = {{3}},
publisher = {{American Physical Society}},
series = {{Physical Review Materials}},
title = {{Anisotropic dynamics of magnetic colloidal cubes studied by X-ray photon correlation spectroscopy}},
url = {{http://dx.doi.org/10.1103/PhysRevMaterials.5.035603}},
doi = {{10.1103/PhysRevMaterials.5.035603}},
volume = {{5}},
year = {{2021}},
}