Strain-Mediated Photocontrol in Core-Shell Prussian Blue Analogue Particles

The Prussian blue analogue (PBA), A$_i$Ni[Cr(CN)$_6$]$_j\cdot n$H$_2$O (\textbf{A}), has been shown to exhibit a pressure-induced decrease in magnetization under both external isotropic pressure\,\footnote{M. Zentkov\'a \emph{et al.}, J. Phys.: Condens. Matter \textbf{19} (2007) 266217; \\ M.~K. Peprah \emph{et al.}, in preparation.} and internal photoinduced structural strain when layered with Rb$_i$Co[Fe(CN)$_6$]$_j\cdot n$H$_2$O (\textbf{B}).\footnote{M. F. Dumont \emph{et al.}, Inorg. Chem. \textbf{50} (2011) 4295; D. M. Pajerowski \emph{et al.}, J. Am. Chem. Soc. \textbf{132} (2010) 4058.} Current investigations of a series of core-shell PBAs, consisting of the photoactive ferrimagnetic \textbf{B} surrounded by ferromagnetic \textbf{A}, quantitatively model this photoinduced phenomenon, which is shown to affect both the magnetic moment and superexchange of roughly half the volume of the \textbf{A} shells. An accurate understanding of the mechanism of strain-mediated photocontrol in these heterostructures will allow the pursuit of rationally designed room temperature photocontrol systems by incorporating pressure-sensitive materials with higher magnetic ordering temperatures.