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Synergy in Photomagnetic/Ferromagnetic Sub-50 nm Core-Multishell Nanoparticles
journal contribution
posted on 2013-09-16, 00:00 authored by Nada Dia, Laurent Lisnard, Yoann Prado, Alexandre Gloter, Odile Stéphan, François Brisset, Hala Hafez, Zeinab Saad, Corine Mathonière, Laure Catala, Talal MallahBased
on nickel hexacyanidochromate and cobalt hexacyanidoferrate Prussian
blue analogues, two series of photomagnetic/ferromagnetic sub-50 nm core multishell coordination nanoparticles have
been synthesized in a surfactant-free one-pot multistep procedure
with good control over the dispersity (10% standard deviation) and
good agreement with the targeted size at each step. The composition
and the valence state of each shell have been probed by different
techniques that have revealed the predominance of CoII-NC-FeIII pairs in a series synthesized without alkali while CoIII-NC-FeII photoswitchable pairs have been successfully
obtained in the photoactive coordination nanoparticles by control
of Cs+ insertion. When compared, the photoinduced behavior
of the latter compound is in good agreement with that of the model
one. Exchange coupling favors a uniform reversal of the magnetization
of the heterostructured nanoparticles, with a large magnetization
brought by a soft ferromagnetic shell and a large coercivity due to
a harder photomagnetic shell. Moreover, a persistent increase of the photoinduced magnetization is observed for the first time
up to the ordering temperature (60 K) of the ferromagnetic component
because of a unique synergy.