1 research outputs found
Control of the Speed of a Light-Induced Spin Transition through Mesoscale Core–Shell Architecture
The rate of the light-induced
spin transition in a coordination
polymer network solid dramatically increases when included as the
core in mesoscale core–shell particles. A series of photomagnetic
coordination polymer core–shell heterostructures, based on
the light-switchable Rb<sub><i>a</i></sub>Co<sub><i>b</i></sub>[FeÂ(CN)<sub>6</sub>]<sub><i>c</i></sub>·<i>m</i>H<sub>2</sub>O (RbCoFe-PBA) as core with
the isostructural K<sub><i>j</i></sub>Ni<sub><i>k</i></sub>[CrÂ(CN)<sub>6</sub>]<sub><i>l</i></sub>·<i>n</i>H<sub>2</sub>O (KNiCr-PBA) as shell, are studied using
temperature-dependent powder X-ray diffraction and SQUID magnetometry.
The core RbCoFe-PBA exhibits a charge transfer-induced spin transition
(CTIST), which can be thermally and optically induced. When coupled
to the shell, the rate of the optically induced transition from low
spin to high spin increases. Isothermal relaxation from the optically
induced high spin state of the core back to the low spin state and
activation energies associated with the transition between these states
were measured. The presence of a shell decreases the activation energy,
which is associated with the elastic properties of the core. Numerical
simulations using an electro-elastic model for the spin transition
in core–shell particles supports the findings, demonstrating
how coupling of the core to the shell changes the elastic properties
of the system. The ability to tune the rate of optically induced magnetic
and structural phase transitions through control of mesoscale architecture
presents a new approach to the development of photoswitchable materials
with tailored properties