Transport Properties of Films of Cobalt Iron Prussian Blue Analogues*

The magnetic and transport properties of films of the bistable, photomagnetic, cobalt iron Prussian blue analogue A$_j$Co$_k$[Fe(CN)$_6$] (A = Na, K, Rb)\footnote{O. Sato \emph{et al}., Science \textbf{272} (1996) 704; O. Sato \emph{et al}., J. Am. Chem. Soc. \textbf{126} (2004) 13176.} on ITO and FTO substrates as a function of temperature \mbox{(100 - 300 K)} and under white light irradition have been studied. The magnetic data show the charge transfer induced spin transition (CTIST) between \mbox{230 - 280 K.} The DC and AC transport measurements also show a transition between different conduction states in the same temperature \mbox{region.} Specifically, the AC data (1 kHz) reveals a smooth hysteresis, which is similar to the response observed in the magnetic data. Upon irradiation with white light, swithching is observed between the two conduction states at low temperature \mbox{T $\sim$ 120 K}.