Effects of Pressure on the Magnetic Properties of Prussian Blue Analogues

Prussian blue analogues (PBAs) have been shown to exhibit interesting magnetic characteristics under various external stimuli: charge transfer induced spin transition (CTIST),\footnote{N. Shimamoto \textit{et al.} Chem. Lett. \textbf{31}, (2002) 486.} a temperature effect; persistent photo-induced magnetism (PPIM),\footnote{O. Sato \textit{et al.} Science \textbf{272} (1996), 704-705.} an optical effect; and pressure induced electron transfer (PIET).\footnote{V. Ksenofontov \textit{et al.} Phys. Rev. B \textbf{68} (2003) 024415.} Our research has established that photocontrol of the magnetic response of CoFe-PBA, can be extended to higher temperatures, accompanied by a decrease in magnetization, using heterostructured PBA particles composed of Rb$_a$Co$_b$[Fe(CN)$_6$]$_c\cdot$$m$H$_2$O cores surrounded by shells of K$_j$Ni$_k$[Cr(CN)$_6$]$_l\cdot$$n$H$_2$O.\footnote{M. F. Dumont \textit{et al.} Inorg. Chem. \textbf{50} (2011) 4295.} This effect is attributed to strain in the shell, induced by a lattice expansion in the core during illumination. We report a similar effect in the core-shells accompanied by PIET under application of external pressure and probe the similarities between optical and pressure effects.